Update Flutter/Dart SDK version.

Author: ryanheise

audio_service_platform_interface/pubspec.yaml

@@ -19,5 +19,5 @@ dev_dependencies:
   build_runner: ^2.0.4
 
 environment:
-  sdk: ">=2.12.0 <3.0.0"
-  flutter: ">=1.12.13+hotfix.5"
+  sdk: ">=2.14.0 <4.0.0"
+  flutter: ">=3.0.0"

audio_service_web/pubspec.yaml

@@ -4,8 +4,8 @@ version: 0.1.1
 homepage: https://github.com/ryanheise/audio_service/tree/master/audio_service_web
 
 environment:
-  sdk: '>=2.12.0 <3.0.0'
-  flutter: ">=2.0.0"
+  sdk: ">=2.14.0 <4.0.0"
+  flutter: ">=3.0.0"
 
 dependencies:
   # Use these deps for local development