Merge branch '6.0' into 6.1

* 6.0:
  Replace duplicate medium configuration
  Update git protocol in URL
  Tell about COMPOSER_ROOT_VERSION when not working on the default branch

Author: javiereguiluz

contributing/code/tests.rst

@@ -24,6 +24,16 @@ tests, such as Doctrine, Twig and Monolog. To do so,
 
     $ composer update
 
+.. tip::
+
+    Dependencies might fail to update and in this case Composer might need you to
+    tell it what Symfony version you are working on.
+    To do so set ``COMPOSER_ROOT_VERSION`` variable, e.g.:
+
+    .. code-block:: terminal
+
+        $ COMPOSER_ROOT_VERSION=4.4.x-dev composer update
+
 .. _running:
 
 Running the Tests

contributing/documentation/overview.rst

@@ -76,7 +76,7 @@ this value accordingly):
 .. code-block:: terminal
 
     $ cd projects/
-    $ git clone git://github.com/YOUR-GITHUB-USERNAME/symfony-docs.git
+    $ git clone git@github.com:YOUR-GITHUB-USERNAME/symfony-docs.git
 
 **Step 3.** Add the original Symfony docs repository as a "Git remote" executing
 this command:

notifier.rst

@@ -555,7 +555,7 @@ specify what channels should be used for specific levels (using
                 ->channelPolicy('high', ['chat/slack'])
                 // Use browser for medium and low notifications
                 ->channelPolicy('medium', ['browser'])
-                ->channelPolicy('medium', ['browser'])
+                ->channelPolicy('low', ['browser'])
             ;
         };