Update dependency html-webpack-plugin to v4

Author: renovate-bot

source/SIL.AppBuilder.Portal.Frontend/package.json

@@ -162,7 +162,7 @@
     "express": "^4.16.3",
     "file-loader": "^6.0.0",
     "fork-ts-checker-webpack-plugin": "^5.0.0",
-    "html-webpack-plugin": "^3.2.0",
+    "html-webpack-plugin": "^4.0.0",
     "html-webpack-root-plugin": "^0.10.0",
     "http-proxy-middleware": "^1.0.0",
     "http-shutdown": "^1.2.0",