3662 [google_maps_flutter_web] update min flutter sdk version to 1.20.0 (cla: yes, p: google_maps_flutter, platform-web, waiting for tree to go green)

3663 [image_picker] Run CocoaPods iOS tests in RunnerUITests target (cla: yes, p: image_picker, platform-ios)

3664 [webview_flutter] Run CocoaPods iOS tests in RunnerUITests target (cla: yes, p: webview_flutter, platform-ios)

3665 [various] Import flutter_test for future compatibility (cla: yes, p: camera, p: in_app_purchase, p: sensors, waiting for tree to go green)

3666 Reorder the checkboxes in the PR template (cla: yes)

3667 Run static analyzer during xctest (cla: yes)