Update dependency webpack-cli to v3.3.4 (GoogleChromeLabs#616)

Update dependency webpack-cli to v3.3.4

Author: surma

package-lock.json

@@ -69,7 +69,7 @@
     "url-loader": "2.0.0",
     "webpack": "4.28.0",
     "webpack-bundle-analyzer": "3.3.2",
-    "webpack-cli": "3.3.2",
+    "webpack-cli": "3.3.4",
     "webpack-dev-server": "3.4.1",
     "worker-plugin": "3.1.0"
   }