1297 Update play-services-maps from 15.+ to 16.1.0 (cla: yes)

1299 [in_app_purchase]restore purchases (cla: yes)

1300 Add my name to firebase_performance and firebase_dynamic_links owners (cla: yes, submit queue)

1302 [google_maps_flutter]ChangeNotifier is replaced with granular callbacks (cla: yes)

1303 [in_app_purchase]retrieve receipt (cla: yes)

1306 [cloud_firestore] Update firebase-firestore to 18.2.0 (cla: yes, submit queue)

1309 [firebase_dynamic_links] Version bump for firebase_dynamic_links PR #1142 (bugfix, cla: yes, flutterfire, submit queue)