Use actions/download-artifact@v4

Author: johnwason

.github/workflows/wheels.yml

@@ -375,7 +375,7 @@ jobs:
       with:
         path: robotraconteur
     - name: Download CI artifacts
-      uses: actions/download-artifact@v2
+      uses: actions/download-artifact@v4
       with:
         path: artifacts/main
     - name: archive wheels