31028 Adds support for generating projects that use AndroidX support libraries (cla: yes, tool, waiting for tree to go green)

31039 Fix bundle id on iOS launch using flutter run (cla: yes, tool)

31095 Add buttons customization to WidgetController and related testing classes (cla: yes, framework)

31227 Adding CupertinoTabController (cla: yes, f: cupertino, framework, severe: API break)

31308 Added font bold when isDefaultAction is true in CupertinoDialogAction (cla: yes, f: cupertino)

31317 Add docs to AppBar (cla: yes, d: api docs, f: material design, framework)

31318 Add BottomSheetTheme to enable theming color, elevation, shape of BottomSheet (cla: yes, f: material design, framework)