Bump korthout/backport-action from 4 to 4.4.0

Bumps [korthout/backport-action](https://github.com/korthout/backport-action) from 4 to 4.4.0.
- [Release notes](https://github.com/korthout/backport-action/releases)
- [Commits](korthout/backport-action@v4...v4.4.0)

---
updated-dependencies:
- dependency-name: korthout/backport-action
  dependency-version: 4.4.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

.github/workflows/port_merged_pull_request.yml

@@ -27,7 +27,7 @@ jobs:
       # Port PR to other branch (ONLY if labeled with "port to")
       # See https://github.com/korthout/backport-action
       - name: Create backport pull requests
-        uses: korthout/backport-action@v4
+        uses: korthout/backport-action@v4.4.0
         with:
           # Trigger based on a "port to [branch]" label on PR
           # (This label must specify the branch name to port to)