[various] Update minimum iOS versions to 12.0 (#5902)
This makes the following mass changes:
- Builds all examples with current stable (3.16.7), to pick up the auto-migration of projects to a minimum of iOS 12.
- In some cases this picks up other boilerplate Xcode project migrations that had never been checked in to those projects.
- Updates all iOS plugin implementations to indicate that they require iOS 12.0 or later.
- Updates all the READMEs of the app-facing versions of those plugins to indicate that iOS 11 will no longer receive implementation updates.
The only code changes are:
- the removal of some @available checks in in_app_purchase_storekit that had become no-ops with the support change
- the removal of a ! in camera_avfoundation Dart code, which is no longer necessary due to changes in nullable field promotion in newer versions of Dart.
These changes are version-exempt [per repo policy](https://github.com/flutter/flutter/wiki/Contributing-to-Plugins-and-Packages#version-and-changelog-updates), so the changelog changes all use NEXT.
[various] Update minimum iOS versions to 12.0 (#5902)
This makes the following mass changes:
- Builds all examples with current stable (3.16.7), to pick up the auto-migration of projects to a minimum of iOS 12.
- In some cases this picks up other boilerplate Xcode project migrations that had never been checked in to those projects.
- Updates all iOS plugin implementations to indicate that they require iOS 12.0 or later.
- Updates all the READMEs of the app-facing versions of those plugins to indicate that iOS 11 will no longer receive implementation updates.
The only code changes are:
- the removal of some @available checks in in_app_purchase_storekit that had become no-ops with the support change
- the removal of a ! in camera_avfoundation Dart code, which is no longer necessary due to changes in nullable field promotion in newer versions of Dart.
These changes are version-exempt [per repo policy](https://github.com/flutter/flutter/wiki/Contributing-to-Plugins-and-Packages#version-and-changelog-updates), so the changelog changes all use NEXT.
[various] Migrate example apps' AppDelegate.swift (#8155)
Migrated by running:
```
dart run script/tool/bin/flutter_plugin_tools.dart build-examples --ios --swift-package-manager
dart run script/tool/bin/flutter_plugin_tools.dart build-examples --macos --swift-package-manager
```
Tests aren't updated as this change should not affect semantics. I will get a test exemption.
Part of https://github.com/flutter/flutter/issues/159173