chore(package): update webpack to version 2.4.1

Closes #62

https://greenkeeper.io/

package.json

@@ -82,7 +82,7 @@
     "sinon-chai": "~2.9.0",
     "style-loader": "~0.16.0",
     "webdriverio": "~4.6.1",
-    "webpack": "~2.3.0",
+    "webpack": "~2.4.1",
     "webpack-dev-middleware": "~1.10.0",
     "webpack-hot-middleware": "~2.18.0"
   }