[image_picker] Pin version of platform_interface. (flutter#2799)

Error (flutter#2796)

* Expose SKError code to client apps

* Format

* Update changelog

* Fix failing tests

* Added version updates in pubspec

* Fix test

[image_picker_platform_interface] Introduce new PickedFile APIs. (flu…

…tter#2791)

* Make API Async, so web can use objectUrls internally, instead of bytes.
* Introduce the PickedFile class to have a more platform agnostic return.
* Modify the platform interface to return PickedFiles.

Run tests with flutter test / flutter test --platform chrome

Co-authored-by: Rody Davis <[email protected]>

[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.