Bump otto-de/purge-deprecated-workflow-runs in /.github/workflows

Bumps [otto-de/purge-deprecated-workflow-runs](https://github.com/otto-de/purge-deprecated-workflow-runs) from 2.0.3 to 2.1.0.
- [Release notes](https://github.com/otto-de/purge-deprecated-workflow-runs/releases)
- [Commits](otto-de/purge-deprecated-workflow-runs@v2.0.3...v2.1.0)

---
updated-dependencies:
- dependency-name: otto-de/purge-deprecated-workflow-runs
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

.github/workflows/housekeeping.yaml

@@ -25,7 +25,7 @@ jobs:
           keep_minimum_runs: 10
 
       - name: Delete unused workflows
-        uses: otto-de/purge-deprecated-workflow-runs@v2.0.3
+        uses: otto-de/purge-deprecated-workflow-runs@v2.1.0
         with:
           token: ${{ github.token }}