build(deps): bump subosito/flutter-action from 1 to 2

Bumps [subosito/flutter-action](https://github.com/subosito/flutter-action) from 1 to 2.
- [Release notes](https://github.com/subosito/flutter-action/releases)
- [Commits](subosito/flutter-action@v1...v2)

---
updated-dependencies:
- dependency-name: subosito/flutter-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/gh-pages.yaml

@@ -10,7 +10,7 @@ jobs:
 
     steps:
       - uses: actions/checkout@v2
-      - uses: subosito/flutter-action@v1
+      - uses: subosito/flutter-action@v2
       - uses: bluefireteam/flutter-gh-pages@v8
         with:
           baseHref: /One-Dungeon/