dependabot: bump tibdex/github-app-token from 1.5.0 to 2.1.0

Bumps [tibdex/github-app-token](https://github.com/tibdex/github-app-token) from 1.5.0 to 2.1.0.
- [Release notes](https://github.com/tibdex/github-app-token/releases)
- [Commits](tibdex/github-app-token@v1.5...v2.1.0)

---
updated-dependencies:
- dependency-name: tibdex/github-app-token
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

.github/workflows/auto-release.yml

@@ -18,7 +18,7 @@ jobs:
     steps:
       - name: GitHub App token
         id: github_app_token
-        uses: tibdex/github-app-token@v1.5.0
+        uses: tibdex/github-app-token@v2.1.0
         with:
           app_id: ${{ secrets.APP_ID }}
           private_key: ${{ secrets.APP_PRIVATE_KEY }}