Bump tibdex/backport from 2.0.3 to 2.0.4

Bumps [tibdex/backport](https://github.com/tibdex/backport) from 2.0.3 to 2.0.4.
- [Release notes](https://github.com/tibdex/backport/releases)
- [Commits](tibdex/backport@v2.0.3...v2.0.4)

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

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

.github/workflows/backport.yml

@@ -35,6 +35,6 @@ jobs:
       github.event.pull_request.merged
       && contains(github.event.label.name, 'backport')
     steps:
-      - uses: tibdex/[email protected].3
+      - uses: tibdex/[email protected].4
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}