chore(package): update html-webpack-plugin to version 4.1.0

Closes #69

Author: greenkeeper[bot]

package.json

@@ -55,7 +55,7 @@
     "eslint-plugin-import": "^2.16.0",
     "file-loader": "^5.0.1",
     "glob": "^7.1.3",
-    "html-webpack-plugin": "^3.2.0",
+    "html-webpack-plugin": "^4.1.0",
     "jest": "^24.1.0",
     "jsdoc": "^3.5.5",
     "lodash": "^4.17.11",