Use V4 download artifact for coverage (#37)

Author: milocress

.github/actions/coverage/action.yaml

@@ -17,7 +17,7 @@ runs:
       uv pip install --upgrade --system pip wheel
       uv pip install --system coverage[toml]==6.5.0
   - name: Download artifacts
-    uses: actions/download-artifact@v3
+    uses: actions/download-artifact@v4
     with:
       path: ${{ inputs.download-path }}
   - name: Generate coverage report