Bump korthout/backport-action in the actions-monthly group

Bumps the actions-monthly group with 1 update: [korthout/backport-action](https://github.com/korthout/backport-action).


Updates `korthout/backport-action` from 4.5.2 to 4.6.0
- [Release notes](https://github.com/korthout/backport-action/releases)
- [Commits](korthout/backport-action@6606540...2e830a1)

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

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

Author: dependabot[bot]

.github/workflows/backport.yml

@@ -32,7 +32,7 @@ jobs:
           echo "OLD_BRANCH=${OLD_BRANCH}" >> $GITHUB_ENV
 
       - name: Create backport pull requests
-        uses: korthout/backport-action@66065406958f46e82238fd59546f5a99e69e22aa  # v4.5.2
+        uses: korthout/backport-action@2e830a1d0b8269505846ddd407a70876913ad1f8  # v4.6.0
         with:
           copy_assignees: true
           copy_labels_pattern: true