update html-webpack-client; remove gitbook-cli

Author: gniezen

package.json

@@ -167,8 +167,7 @@
     "file-loader": "6.2.0",
     "flux-standard-action": "2.1.2",
     "ftp": "0.3.10",
-    "gitbook-cli": "2.3.2",
-    "html-webpack-plugin": "3.2.0",
+    "html-webpack-plugin": "4.5.2",
     "jest": "26.6.3",
     "json-loader": "0.5.7",
     "less-loader": "6.2.0",