Used Flutter Migrate tool and fixed flutter_picker in pubspec.yaml

android/.gitignore

@@ -9,3 +9,5 @@ GeneratedPluginRegistrant.java
 # Remember to never publicly share your keystore.
 # See https://flutter.dev/docs/deployment/android#reference-the-keystore-from-the-app
 key.properties
+**/*.keystore
+**/*.jks