Install webpack-merge

- Installed `webpack-merge` as optional dependency.

Author: iamWing

package-lock.json

@@ -84,7 +84,8 @@
     "tsconfig-paths": "^4.0.0",
     "tsconfig-paths-webpack-plugin": "^3.5.2",
     "webpack": "^5.73.0",
-    "webpack-cli": "^4.10.0"
+    "webpack-cli": "^4.10.0",
+    "webpack-merge": "^5.8.0"
   },
   "repository": {
     "type": "git",