Bump subosito/flutter-action in the github-actions group (#1784)

Bumps the github-actions group with 1 update: [subosito/flutter-action](https://github.com/subosito/flutter-action).


Updates `subosito/flutter-action` from 2.19.0 to 2.21.0
- [Release notes](https://github.com/subosito/flutter-action/releases)
- [Commits](subosito/flutter-action@e938fdf...fd55f4c)

---
updated-dependencies:
- dependency-name: subosito/flutter-action
  dependency-version: 2.21.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
  dependency-group: github-actions
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

.github/workflows/cronet.yml

@@ -38,7 +38,7 @@ jobs:
         with:
           distribution: 'zulu'
           java-version: '17'
-      - uses: subosito/flutter-action@e938fdf56512cc96ef2f93601a5a40bde3801046
+      - uses: subosito/flutter-action@fd55f4c5af5b953cc57a2be44cb082c8f6635e8e
         with:
           channel: 'stable'
       - id: install

.github/workflows/cupertino.yml

@@ -39,7 +39,7 @@ jobs:
         os: [macos-13, macos-latest]
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
-      - uses: subosito/flutter-action@e938fdf56512cc96ef2f93601a5a40bde3801046
+      - uses: subosito/flutter-action@fd55f4c5af5b953cc57a2be44cb082c8f6635e8e
         with:
           flutter-version: ${{ matrix.flutter-version }}
           channel: 'stable'
@@ -71,7 +71,7 @@ jobs:
         flutter-version: ["3.24.0", "any"]
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
-      - uses: subosito/flutter-action@e938fdf56512cc96ef2f93601a5a40bde3801046
+      - uses: subosito/flutter-action@fd55f4c5af5b953cc57a2be44cb082c8f6635e8e
         with:
           flutter-version: ${{ matrix.flutter-version }}
           channel: 'stable'

.github/workflows/dart.yml

@@ -33,7 +33,7 @@ jobs:
         with:
           distribution: 'zulu'
           java-version: '17'
-      - uses: subosito/flutter-action@e938fdf56512cc96ef2f93601a5a40bde3801046
+      - uses: subosito/flutter-action@fd55f4c5af5b953cc57a2be44cb082c8f6635e8e
         with:
           channel: 'stable'
       - id: install