Bump actions/download-artifact from 4.1.7 to 4.1.8 (#405)

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 4.1.7 to 4.1.8.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v4.1.7...v4.1.8)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/tests.yaml

@@ -76,7 +76,7 @@ jobs:
       - name: Install dependencies
         run: pip install -U -r requirements-coverage.txt
       - name: Download all coverage artifacts
-        uses: actions/download-artifact@v4.1.7
+        uses: actions/download-artifact@v4.1.8
       - name: Combine Linux coverage results
         run: |
           coverage combine coverage-linux*/.coverage