Bump uhafner/autograding-github-action from 1.7.1 to 1.7.3

Bumps [uhafner/autograding-github-action](https://github.com/uhafner/autograding-github-action) from 1.7.1 to 1.7.3.
- [Release notes](https://github.com/uhafner/autograding-github-action/releases)
- [Commits](v1.7.1...v1.7.3)

---
updated-dependencies:
- dependency-name: uhafner/autograding-github-action
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

.github/workflows/ci.yml

@@ -20,7 +20,7 @@ jobs:
       - name: Test setup
         run: sh copy_files.sh
       - name: Run Autograding
-        uses: uhafner/[email protected].1
+        uses: uhafner/[email protected].3
         with:
           TOKEN: ${{ secrets.GITHUB_TOKEN }}
           HEAD_SHA: ${{github.event.pull_request.head.sha}}