ci: bump actions/create-github-app-token in the actions group

Bumps the actions group with 1 update: [actions/create-github-app-token](https://github.com/actions/create-github-app-token).


Updates `actions/create-github-app-token` from 1 to 2
- [Release notes](https://github.com/actions/create-github-app-token/releases)
- [Commits](https://github.com/actions/create-github-app-token/compare/v1...v2)

---
updated-dependencies:
- dependency-name: actions/create-github-app-token
  dependency-version: '2'
  dependency-type: direct:production
  update-type: version-update:semver-major
  dependency-group: actions
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/backport.yml

@@ -17,7 +17,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Create app token
-        uses: actions/create-github-app-token@v1
+        uses: actions/create-github-app-token@v2
         id: app-token
         with:
           app-id: ${{ vars.BACKPORT_APP }}