Bump subosito/flutter-action in the github-actions group

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


Updates `subosito/flutter-action` from 2.17.0 to 2.18.0
- [Release notes](https://github.com/subosito/flutter-action/releases)
- [Commits](subosito/flutter-action@74af56c...f2c4f66)

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

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/flutter_markdown.yaml

@@ -32,7 +32,7 @@ jobs:
 
       # Install the Flutter SDK using the subosito/flutter-action GitHub action.
       - name: install the flutter sdk
-        uses: subosito/flutter-action@74af56c5ed2697ba4621264652728e8d217e53d3
+        uses: subosito/flutter-action@f2c4f6686ca8e8d6e6d0f28410eeef506ed66aff
         with:
           channel: 'beta'