Fix deprecation v2 of actions/download-artifact

Author: sfmok

.github/workflows/ci.yml

@@ -77,7 +77,7 @@ jobs:
           fetch-depth: 2
 
       - name: "Download coverage files"
-        uses: "actions/download-artifact@v2"
+        uses: "actions/download-artifact@v4"
         with:
           path: "reports"