43461 Fixed usage of optional types in swift integration test.

13423 Automatically destroy FlutterEngine when created by FlutterActivity or FlutterFragment.

42958 Turn off bitcode for integration tests and add-to-app templates

13428 Set the install name at link time for darwin dylibs

41333 Merge Flutter assets in add to app

39747 Fix type mismatch in Gradle

39986 Enable Proguard by default on release mode

40181 Update Kotlin and Gradle version

40282 Flip the default for proguard

40440 Rename useProguard method, so Gradle doesn’t get confused

40453 Enable R8

40610 Enable the resource shrinker