build(deps): bump actions/checkout from 2.3.4 to 2.4.0

Bumps [actions/checkout](https://github.com/actions/checkout) from 2.3.4 to 2.4.0.
- [Release notes](https://github.com/actions/checkout/releases)
- [Changelog](https://github.com/actions/checkout/blob/main/CHANGELOG.md)
- [Commits](https://github.com/actions/checkout/compare/v2.3.4...v2.4.0)

---
updated-dependencies:
- dependency-name: actions/checkout
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

.github/workflows/trigger-gitlab.yml

@@ -42,7 +42,7 @@ jobs:
       SCHUTZBOT_SSH_KEY: ${{ secrets.SCHUTZBOT_SSH_KEY }}
     steps:
       - name: Clone repository
-        uses: actions/checkout@v2
+        uses: actions/checkout@v2.4.0
         with:
           # otherwise we are testing target branch instead of the PR branch (see pull_request_target trigger)
           ref: ${{ github.event.pull_request.head.sha }}