[in_app_purchase] Update typo in example main.dart (flutter#3073)

* Update main.dart

Documentation typo.

* Update CHANGELOG.md

* Update pubspec.yaml

[video_player] Set playback speed (flutter#3084)

[video_player_web] Implement playback speed (flutter#3081)

[video_player] Fix tests on master (flutter#3082)

The previous push removed a class used for testing in the video_player package. This PR fixes tests to use the new class.

[video_player_platform_interface] Add setPlaybackSpeed method (flutte…

…r#3032)

[file_selector_platform_interface] Add platform interface for new fil…

…e_selector plugin (flutter#2995)

[url_launcher] Document why canLaunch can return false on Android API…

… 30 (flutter#3040)

This PR adds extra documentation to the canLaunch method, explaining that (from Android API 30) false is returned when the package visibility is not managed properly.

Starting from Android API 30, apps should explicitly list which other apps it wants to query or interact with, by specifying them in the AndroidManifest.xml file. More information can be found in the Manage package visibility article in the Android documentation.

[url_launcher_web] Improve attribution of package:platform_detect's c…

…ode. (flutter#3075)

[shared_preferences] Endorse Windows (flutter#3059)

Adds endorsement, and manual registration, of
shared_preferences_windows.

Fixes flutter/flutter#41719

[shared_preferences] Endorse Windows (flutter#3059)

Adds endorsement, and manual registration, of
shared_preferences_windows.

Fixes flutter/flutter#41719