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

Closes #594

Author: greenkeeper[bot]

package.json

@@ -151,7 +151,7 @@
     "extract-text-webpack-plugin": "^4.0.0-beta.0",
     "file-loader": "^3.0.1",
     "font-awesome": "^4.7.0",
-    "html-webpack-plugin": "^3.1.0",
+    "html-webpack-plugin": "^4.0.4",
     "husky": "^1.3.1",
     "identity-obj-proxy": "^3.0.0",
     "jest": "^24.7.1",