chore(deps): update dependency html-webpack-plugin to v4.2.1

Author: renovate-bot

package-lock.json

@@ -40,7 +40,7 @@
     "friendly-errors-webpack-plugin": "1.7.0",
     "gulp": "4.0.2",
     "gulp-typescript": "6.0.0-alpha.1",
-    "html-webpack-plugin": "4.0.4",
+    "html-webpack-plugin": "4.2.1",
     "husky": "4.2.3",
     "koa-webpack-dev-middleware": "2.0.2",
     "koa-webpack-hot-middleware": "1.0.3",