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

Closes #167

Author: greenkeeper[bot]

package.json

@@ -66,7 +66,7 @@
     "eslint-config-react": "1.1.7",
     "eslint-loader": "3.0.3",
     "eslint-plugin-react": "^7.14.2",
-    "html-webpack-plugin": "3.2.0",
+    "html-webpack-plugin": "4.0.1",
     "jest": "^24.9.0",
     "jest-styled-components": "^6.3.3",
     "prettier": "^1.17.1",