Replace 'master' to 'main' in md files.

Author: ilopX

README.md

@@ -5,27 +5,27 @@ It contains **Dart** examples for all classic **GoF** design patterns.
 # Implementation checklist:
 - [ ] **Creation**
     - [ ] **Abstract Factory**
-    - [x] **Builder** - [[Color Text Format](https://github.com/RefactoringGuru/design-patterns-dart/tree/master/patterns/builder/color_text_format)]
+    - [x] **Builder** - [[Color Text Format](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/builder/color_text_format)]
     - [ ] **Factory Method**
-    - [x] **Prototype**] - [[Shapes](https://github.com/RefactoringGuru/design-patterns-dart/tree/master/patterns/prototype/shapes)] 
+    - [x] **Prototype**] - [[Shapes](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/prototype/shapes)] 
     - [ ] **Singleton**
 - [ ]  **Behavioral**
-    - [x] **Chain of Responsibility** - [[Server Middleware](https://github.com/RefactoringGuru/design-patterns-dart/tree/master/patterns/chain_of_responsibility/server_middleware)]
-    - [x] **Command** - [[Text Editor](https://github.com/RefactoringGuru/design-patterns-dart/tree/master/patterns/command/text_editor)] 
+    - [x] **Chain of Responsibility** - [[Server Middleware](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/chain_of_responsibility/server_middleware)]
+    - [x] **Command** - [[Text Editor](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/command/text_editor)] 
     - [ ] Interpreter
     - [ ] **Iterator**
     - [ ] **Mediator**
-    - [x] **Memento** - [[Conceptual](https://github.com/RefactoringGuru/design-patterns-dart/tree/master/patterns/memento/conceptual)] [[Memento Editor](https://github.com/RefactoringGuru/design-patterns-dart/tree/master/patterns/memento/memento_editor)] 
-    - [x] **Observer** - [[Open-Close Editor Events](https://github.com/RefactoringGuru/design-patterns-dart/tree/master/patterns/observer/open_close_editor_events)] [[AppObserver](https://github.com/RefactoringGuru/design-patterns-dart/tree/master/patterns/observer/app_observer)] [[Subscriber Flutter Widget](https://github.com/RefactoringGuru/design-patterns-dart/tree/master/patterns/observer/subscriber_flutter_widget)]
+    - [x] **Memento** - [[Conceptual](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/memento/conceptual)] [[Memento Editor](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/memento/memento_editor)] 
+    - [x] **Observer** - [[Open-Close Editor Events](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/observer/open_close_editor_events)] [[AppObserver](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/observer/app_observer)] [[Subscriber Flutter Widget](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/observer/subscriber_flutter_widget)]
     - [ ] **State**
     - [ ] **Template Method**
     - [ ] **Visitor**
     - [ ] **Strategy**
 - [ ] **Structural**
-    - [x] **Adapter** - [[Text Graphics](https://github.com/RefactoringGuru/design-patterns-dart/tree/master/patterns/adapter/text_graphics)] [[Square Round conflict](https://github.com/RefactoringGuru/design-patterns-dart/tree/master/patterns/adapter/square_round_conflict)] [[Flutter Adapter](https://github.com/RefactoringGuru/design-patterns-dart/tree/master/patterns/adapter/flutter_adapter)] 
-    - [x] **Bridge** - [[Remote Device Control](https://github.com/RefactoringGuru/design-patterns-dart/tree/master/patterns/bridge/devices_remote_control)] [[Clock](https://github.com/RefactoringGuru/design-patterns-dart/tree/master/patterns/bridge/clock)] 
-    - [x] **Composite** - [[Image Editor](https://github.com/RefactoringGuru/design-patterns-dart/tree/master/patterns/composite/image_editor)] [[Products and Boxes](https://github.com/RefactoringGuru/design-patterns-dart/tree/master/patterns/composite/products_and_boxes)] 
-    - [x] **Decorator** - [[Data Source Decoder](https://github.com/RefactoringGuru/design-patterns-dart/tree/master/patterns/decorator/data_source_decoder)]
+    - [x] **Adapter** - [[Text Graphics](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/adapter/text_graphics)] [[Square Round conflict](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/adapter/square_round_conflict)] [[Flutter Adapter](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/adapter/flutter_adapter)] 
+    - [x] **Bridge** - [[Remote Device Control](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/bridge/devices_remote_control)] [[Clock](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/bridge/clock)] 
+    - [x] **Composite** - [[Image Editor](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/composite/image_editor)] [[Products and Boxes](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/composite/products_and_boxes)] 
+    - [x] **Decorator** - [[Data Source Decoder](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/decorator/data_source_decoder)]
     - [ ] **Facade**
     - [ ] **Flyweight**
     - [ ] **Proxy**

patterns/adapter/flutter_adapter/README.md

@@ -9,8 +9,8 @@ This example shows how to adapt a non-reactive classic type application for Flut
 
 ### Dependency
 This complex example includes these implementations:
-- [[AppObserver](https://github.com/RefactoringGuru/design-patterns-dart/tree/master/patterns/observer/app_observer)]
-- [[SubscriberWidget](https://github.com/RefactoringGuru/design-patterns-dart/tree/master/patterns/observer/subscriber_flutter_widget)]
+- [[AppObserver](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/observer/app_observer)]
+- [[SubscriberWidget](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/observer/subscriber_flutter_widget)]
 
 ### Online demo:
 Click on the picture to see a [demo](https://refactoringguru.github.io/design-patterns-dart/#/adapter/flutter_adapter).

patterns/bridge/devices_remote_control/README.md

@@ -1,5 +1,5 @@
 # Bridge pattern
-This example rewrite from [java example](https://github.com/RefactoringGuru/design-patterns-java/tree/master/src/refactoring_guru/bridge/example)
+This example rewrite from [java example](https://github.com/RefactoringGuru/design-patterns-java/tree/main/src/refactoring_guru/bridge/example)
 But removed the ability to use null for devices. Instead, the EmptyDevice class is used.
 
 ### Remote device example

patterns/chain_of_responsibility/server_middleware/README.md

@@ -8,7 +8,7 @@ Chain of Responsibility is a behavioral design pattern that lets you pass reques
 https://refactoring.guru/design-patterns/chain-of-responsibility?#problem
 
 ### Origin source code:
-This example rewrite from [java example](https://github.com/RefactoringGuru/design-patterns-java/tree/master/src/refactoring_guru/chain_of_responsibility/example)
+This example rewrite from [java example](https://github.com/RefactoringGuru/design-patterns-java/tree/main/src/refactoring_guru/chain_of_responsibility/example)
 
 ### Diagram:
 ![image](https://user-images.githubusercontent.com/8049534/149488654-7ff5f659-4086-4d1a-ae44-326c71fb880a.png)

patterns/command/text_editor/README.md

@@ -11,7 +11,7 @@ possible to revert an operation if needed.
 More detailed explanation on [RefactoringGuru](https://refactoring.guru/design-patterns/command?#pseudocode).
 
 ## Origin source code:
-This example rewrite from [java example](https://github.com/RefactoringGuru/design-patterns-java/tree/master/src/refactoring_guru/command/example).
+This example rewrite from [java example](https://github.com/RefactoringGuru/design-patterns-java/tree/main/src/refactoring_guru/command/example).
 But slightly changed, see the class diagram.
 
 ## Diagram:

patterns/composite/image_editor/README.md

@@ -5,7 +5,7 @@ Composite is a structural design pattern that lets you compose objects into tree
 https://refactoring.guru/design-patterns/composite?#pseudocode
 
 ## Origin source code:
-This example rewrite from [java example](https://github.com/RefactoringGuru/design-patterns-java/tree/master/src/refactoring_guru/composite/example)
+This example rewrite from [java example](https://github.com/RefactoringGuru/design-patterns-java/tree/main/src/refactoring_guru/composite/example)
 
 ### Diagram:
 ![image](https://user-images.githubusercontent.com/8049534/149174388-25ca21b1-d762-40b5-a853-528abe18b66c.png)

patterns/memento/memento_editor/README.md

@@ -11,8 +11,8 @@ Click on the picture to see the [demo](https://RefactoringGuru.github.io/design-
 
 ### Dependency Patterns
 This complex example includes these implementations:
-- [[AppObserver](https://github.com/RefactoringGuru/design-patterns-dart/tree/master/patterns/observer/app_observer)]
-- [[SubscriberWidget](https://github.com/RefactoringGuru/design-patterns-dart/tree/master/patterns/observer/subscriber_flutter_widget)]
+- [[AppObserver](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/observer/app_observer)]
+- [[SubscriberWidget](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/observer/subscriber_flutter_widget)]
 
 ### Diagram:
 ![image](https://user-images.githubusercontent.com/8049534/165758516-1de543f5-666d-4e07-958d-2d8fceb73af9.png)

patterns/observer/open_close_editor_events/README.md

@@ -9,7 +9,7 @@ changes in its state.
 More detailed explanation on [RefactoringGuru](https://refactoring.guru/design-patterns/observer?#pseudocode).
 
 ### Origin source code:
-This example rewrite from [java example](https://github.com/RefactoringGuru/design-patterns-java/tree/master/src/refactoring_guru/observer/example).
+This example rewrite from [java example](https://github.com/RefactoringGuru/design-patterns-java/tree/main/src/refactoring_guru/observer/example).
 
 ### Diagram:
 ![image](https://user-images.githubusercontent.com/8049534/150955865-7fbb29f3-ed48-4317-a356-cbb9cc79ed11.png)

patterns/observer/subscriber_flutter_widget/README.md

@@ -7,7 +7,7 @@ Tutorial: [here](https://refactoring.guru/design-patterns/observer).
 ## Subscriber flutter widget example 
 This is a complex example of an Observer pattern, connected to a Flutter application. The example includes,
 the previously implemented **AppObserver** example pattern, 
-which you can see [here](https://github.com/RefactoringGuru/design-patterns-dart/tree/master/patterns/observer/app_observer).
+which you can see [here](https://github.com/RefactoringGuru/design-patterns-dart/tree/main/patterns/observer/app_observer).
 
 ### Online demo:
 Click on the picture to see a [demo](https://RefactoringGuru.github.io/design-patterns-dart/#/observer/subscriber_flutter_widget).