Fix warnings for non-nullable bindings (flutter#1972)

* Fix warnings for non-nullable bindings

* Update CHANGELOG.md

* Update null_safe_test.dart

* format

* Update main.dart

* address feedback

* x

* address feedback

* undo auto formatting

* x

* fix formatting

* add missing `lcov_parser` dev dependency

Fix warnings for non-nullable bindings (flutter#1972)

* Fix warnings for non-nullable bindings

* Update CHANGELOG.md

* Update null_safe_test.dart

* format

* Update main.dart

* address feedback

* x

* address feedback

* undo auto formatting

* x

* fix formatting

* add missing `lcov_parser` dev dependency

Fix warnings for non-nullable bindings (flutter#1972)

* Fix warnings for non-nullable bindings

* Update CHANGELOG.md

* Update null_safe_test.dart

* format

* Update main.dart

* address feedback

* x

* address feedback

* undo auto formatting

* x

* fix formatting

* add missing `lcov_parser` dev dependency

Fix warnings for non-nullable bindings (flutter#1972)

* Fix warnings for non-nullable bindings

* Update CHANGELOG.md

* Update null_safe_test.dart

* format

* Update main.dart

* address feedback

* x

* address feedback

* undo auto formatting

* x

* fix formatting

* add missing `lcov_parser` dev dependency

[cross_file] fixed lastModified unimplemented error description (flut…

…ter#2032)

Fix warnings for non-nullable bindings (flutter#1972)

* Fix warnings for non-nullable bindings

* Update CHANGELOG.md

* Update null_safe_test.dart

* format

* Update main.dart

* address feedback

* x

* address feedback

* undo auto formatting

* x

* fix formatting

* add missing `lcov_parser` dev dependency

[pigeon] Added basic C++ support (flutter#476)

[flutter_template_images] Minor cleanup (flutter#1951)

[pigeon] Minor Obj-C simplification (flutter#1980)

[flutter_template_images] Add macOS app icon assets (flutter#1930)

Adds the the AppIcon assets in the macOS app template while
simultaneously updating them to meet Apple's icon guidelines as of macOS
Big Sur.

Ref: https://developer.apple.com/design/human-interface-guidelines/macos/icons-and-images/app-icon/

Issue: flutter/flutter#103371