Bump actions/download-artifact from 3.0.0 to 4.1.8

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 3.0.0 to 4.1.8.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v3.0.0...v4.1.8)

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

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

.github/workflows/tests.yaml

@@ -100,7 +100,7 @@ jobs:
           echo "Failed to restore Python venv from cache"
           exit 1
       - name: Download all coverage artifacts
-        uses: actions/download-artifact@v3.0.0
+        uses: actions/download-artifact@v4.1.8
       - name: Combine coverage results
         run: |
           . venv/bin/activate