chore(deps): update actions/download-artifact action to v5

Author: renovate[bot]

.github/workflows/ci.yml

@@ -62,7 +62,7 @@ jobs:
           PYTHON_VERSION: 3.12
       - name: Download all artifacts
         # Downloads coverage1, coverage2, etc.
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@v5
       - name: Run coverage
         run: make ci_coverage
       - uses: codecov/codecov-action@v4