update changelog and pubspec

Author: renefloor

flutter_cache_manager_firebase/CHANGELOG.md

@@ -1,3 +1,6 @@
+## [2.0.0] - 2021-05-28
+* Update to null safety
+
 ## [1.1.0] - 2021-01-14
 * Update Firebase dependency
 

flutter_cache_manager_firebase/pubspec.yaml

@@ -1,6 +1,6 @@
 name: flutter_cache_manager_firebase
 description: CacheManager implementation for firebase_storage. Uses the gs:// as key and translates to https://
-version: 2.0.0-nullsafety.0
+version: 2.0.0
 homepage: https://github.com/Baseflow/flutter_cache_manager
 
 environment:
@@ -9,8 +9,8 @@ environment:
 dependencies:
   flutter:
     sdk: flutter
-  flutter_cache_manager: ^3.0.0-nullsafety.0
-  firebase_storage: ">=8.0.0 <9.0.0"
+  flutter_cache_manager: ^3.0.0
+  firebase_storage: ^8.0.0
   path_provider: ^2.0.0
   path: ^1.8.0