[image_picker] support android V2 embedding (flutter#2430)

[webview_flutter] Setup XCTests (flutter#2445)

[video_player] Fixes video initialization future stall. (flutter#2134)

Fixes issue where `initialize()` `Future` stalls when failing to load source data and does not throw error.

For example if the network is offline and you try to load a video. The video will attempt to load the source on Android through ExoPlayer. This error of failing to load is reported through the event stream to the client. However, this does not complete the initialization `Completer` leaving the `Future stalled waiting for the completer to complete which it never will.

[In_app_purchases] migrate to Play Billing Library 2.0. (flutter#2287)

Migrate away from deprecated `BinaryMessages` (flutter#2444)

* BinaryMessages migration for package:connectivity

* Migrate package:sensors from deprecated BinaryMessages

* Migrate package:webview_flutter from deprecated BinaryMessages

* Only do patch bumps

Migrate away from deprecated `BinaryMessages` (flutter#2444)

* BinaryMessages migration for package:connectivity

* Migrate package:sensors from deprecated BinaryMessages

* Migrate package:webview_flutter from deprecated BinaryMessages

* Only do patch bumps

Migrate away from deprecated `BinaryMessages` (flutter#2444)

* BinaryMessages migration for package:connectivity

* Migrate package:sensors from deprecated BinaryMessages

* Migrate package:webview_flutter from deprecated BinaryMessages

* Only do patch bumps

[in_app_purchase]Change a comment. (flutter#2329)

[google_sign_in] Pass the client id to the platform interface. (flutt…

…er#2427)

The param exists in the platform interface but there was no way to pass
anything to clientId through the external interface.

[url_launcher_platform_interface] use non static token for platform i…

…nterface (flutter#2418)