github workflows: disable runtime upgrade test for antioch

.github/workflows/run-network-tests.yml

@@ -79,6 +79,7 @@ jobs:
           path: joystream-node-docker-image.tar.gz
 
   basic_runtime_with_upgrade:
+    if: ${{ false }}  # Antioch will be a new chain
     name: Integration Tests (Runtime Upgrade)
     needs: build_images
     runs-on: ubuntu-latest