chore(package): update html-webpack-plugin to version 4.0.1

Closes #533

Author: greenkeeper[bot]

package.json

@@ -65,7 +65,7 @@
     "faker": "^4.1.0",
     "file-loader": "1.1.5",
     "gh-pages": "^1.0.0",
-    "html-webpack-plugin": "^2.28.0",
+    "html-webpack-plugin": "^4.0.1",
     "istanbul": "1.1.0-alpha.1",
     "jsdom": "11.5.1",
     "material-ui": "next",