android_intent_plus: fix platform dependency version

Author: jpnurmi

packages/android_intent_plus/pubspec.yaml

@@ -15,7 +15,7 @@ flutter:
 dependencies:
   flutter:
     sdk: flutter
-  platform: ^3.0.0-nullsafety.2
+  platform: ^2.0.0
   meta: ^1.0.5
 dev_dependencies:
   test: ^1.3.0