[Video_player] Upgraded to exoPlayer 2.17.0 (flutter#5011)

[camera] Update README (flutter#4988)

[video_player] Platform interface changes to fix Android rotation for…

… videos recorded in landscapeRight (flutter#4634)

[google_maps_flutter] Fix iOS crash by observing map frame change onl…

…y once (flutter#3426)

[flutter_plugin_tool] Add custom-test command (flutter#5058)

[in_app_purchase] Implements transaction caching for StoreKit (flutte…

…r#4985)

[video_player] Rename internal method channels (flutter#5045)

[video_player] Rename internal method channels (flutter#5045)

[in_app_purchase] Adds additional explanation on the importance of co…

…mpleting a purchase (flutter#5017)

[file_selector] Update macOS README and example (flutter#5034)