.github: Bump korthout/backport-action from 4.5.2 to 4.6.0

Bumps [korthout/backport-action](https://github.com/korthout/backport-action) from 4.5.2 to 4.6.0.
- [Release notes](https://github.com/korthout/backport-action/releases)
- [Commits](6606540695...2e830a1d0b)

---
updated-dependencies:
- dependency-name: korthout/backport-action
  dependency-version: 4.6.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

.github/workflows/backport.yml

@@ -49,7 +49,7 @@ jobs:
 
       - name: Create backport PRs
         id: backport
-        uses: korthout/backport-action@66065406958f46e82238fd59546f5a99e69e22aa # v4.5.2
+        uses: korthout/backport-action@2e830a1d0b8269505846ddd407a70876913ad1f8 # v4.6.0
         with:
           # Config README: https://github.com/korthout/backport-action#backport-action
           add_author_as_reviewer: true