Merge pull request #4 from dfdgsdfg/3

#3 fix. update remote config, firebase core dependiences.

pubspec.yaml

@@ -1,6 +1,6 @@
 name: fake_firebase_remote_config
 description: Fake Firebase Remote Config for use during Flutter unit & widget tests.
-version: 2.0.0
+version: 2.1.0
 homepage: https://philippbauer.me/
 repository: https://github.com/CiriousJoker/fake_firebase_remote_config
 
@@ -9,8 +9,8 @@ environment:
   flutter: ">=1.17.0"
 
 dependencies:
-  firebase_core: ">=0.0.1 <3.0.0"
-  firebase_remote_config: ">=4.0.0 <5.0.0"
+  firebase_core: ">=0.0.1 <4.0.0"
+  firebase_remote_config: ">=4.0.0 <6.0.0"
   flutter:
     sdk: flutter