chore(package): update extract-text-webpack-plugin to version 3.0.1

Closes #27

Author: greenkeeper[bot]

package.json

@@ -43,7 +43,7 @@
     "eslint-plugin-import": "^2.2.0",
     "eslint-watch": "^3.0.1",
     "express": "4.15.2",
-    "extract-text-webpack-plugin": "^2.1.0",
+    "extract-text-webpack-plugin": "^3.0.1",
     "html-webpack-plugin": "^2.28.0",
     "jsdom": "^10.0.0",
     "json-schema-faker": "^0.4.1",