Error (flutter#2796)

* Expose SKError code to client apps

* Format

* Update changelog

* Fix failing tests

* Added version updates in pubspec

* Fix test

[webview_flutter] use hard coded values in `setAndGetScrollPosition` …

…test (flutter#2785)

[google_maps_flutter] Android: only destroy mapView once (flutter#2772)

[google_maps_flutter] Android: only destroy mapView once (flutter#2772)

[google_maps_flutter] Android: only destroy mapView once (flutter#2772)

[google_maps_flutter] Android: only destroy mapView once (flutter#2772)

[google_maps_flutter] Android: only destroy mapView once (flutter#2772)

[path_provider] path provider linux implementation in dart (flutter#2589

)

Adds a pure-Dart path_provider_linux, to use as a federated Linux implementation of path_provider.

[google_maps_flutter] Android: only destroy mapView once (flutter#2772)

[google_maps_flutter] Android: only destroy mapView once (flutter#2772)