Support Android embedding v2

[mikolak]

Plugin should probably support the new embedding - need more research.

Example links for knowledge:
https://flutter.dev/docs/development/packages-and-plugins/plugin-api-migration
https://stackoverflow.com/questions/59988211/what-is-the-difference-between-flutter-android-embedding-v1-and-v2

This one seems most promising: https://medium.com/flutter/modern-flutter-plugin-development-4c3ee015cf5a

[MoralCode]

the warning also links to https://flutter.dev/go/android-project-migration

[ride4sun]

Did somebody create a branch of this package and fix these issues like embedding and null safety?
Seems like nothing changing here