Update dependency html-webpack-plugin to v4

Author: renovate-bot

{{ cookiecutter.project_slug }}/client/package-lock.json

@@ -45,7 +45,7 @@
     "eslint-plugin-react-hooks": "2.5.1",
     "fork-ts-checker-notifier-webpack-plugin": "2.0.0",
     "fork-ts-checker-webpack-plugin": "4.1.0",
-    "html-webpack-plugin": "3.2.0",
+    "html-webpack-plugin": "4.0.1",
     "jest": "25.1.0",
     "npm-check": "5.9.2",
     "redux-devtools": "3.5.0",