chore(package): update webpack to version 4.40.2

Closes #229

Author: greenkeeper[bot]

package.json

@@ -61,7 +61,7 @@
     "react-addons-test-utils": "15.4.1",
     "react-dom": "16.2.0",
     "sinon": "1.17.6",
-    "webpack": "1.14.0",
+    "webpack": "4.40.2",
     "webpack-dev-server": "1.16.2"
   },
   "peerDependencies": {