Bump tibdex/backport from 1 to 2 (#493)

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

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

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

Author: dependabot[bot]

.github/workflows/backport.yml

@@ -11,6 +11,6 @@ jobs:
     if: github.event.pull_request.merged
     steps:
       - name: Backport
-        uses: tibdex/backport@v1
+        uses: tibdex/backport@v2
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}