chore(package): update webpack to version 2.3.3

https://greenkeeper.io/

package.json

@@ -44,7 +44,7 @@
     "mocha": "~3.2.0",
     "nyc": "~10.2.0",
     "pre-commit": "~1.2.0",
-    "webpack": "~2.3.2",
+    "webpack": "~2.3.3",
     "zuul": "~3.11.1"
   }
 }