2328 Update documentation for connectivity (cla: yes)

2329 [in_app_purchase]Change a comment. (cla: yes, in review)

2331 [in_app_purchase]Update json_annotation version (cla: yes)

2332 Web implementation of shared_preferences (cla: yes)

2334 [CI] Adds task to build and test plugins with macos implementations (WIP, cla: yes)

2335 [google_sign_in]Update google_sign_in_example name in pubspec.yaml (cla: yes)

2337 [webview_flutter] Make it more explicit that webview keyboard is not ready for production (cla: yes)

2338 [ android_alarm_manager ] Loosen Flutter SDK lower bound, update README (cla: yes)