fix(package): update html-webpack-plugin to version 4.0.4

Closes #99

Author: greenkeeper[bot]

package.json

@@ -42,7 +42,7 @@
     "findup": "^0.1.5",
     "fs-extra": "^1.0.0",
     "handlebars": "^4.0.5",
-    "html-webpack-plugin": "^2.24.1",
+    "html-webpack-plugin": "^4.0.4",
     "http-proxy-middleware": "^0.17.2",
     "inquirer": "^1.2.2",
     "json-loader": "^0.5.4",