chore(deps): bump webpack-merge in /packages/stark-build

Bumps [webpack-merge](https://github.com/survivejs/webpack-merge) from 4.2.2 to 5.7.3.
- [Release notes](https://github.com/survivejs/webpack-merge/releases)
- [Changelog](https://github.com/survivejs/webpack-merge/blob/develop/CHANGELOG.md)
- [Commits](survivejs/webpack-merge@v4.2.2...v5.7.3)

Signed-off-by: dependabot[bot] <support@github.com>

packages/stark-build/package.json

@@ -35,7 +35,7 @@
     "tslint-loader": "^3.6.0",
     "tslint-sonarts": "^1.8.0",
     "webpack-bundle-analyzer": "^3.0.4",
-    "webpack-merge": "^4.2.1",
+    "webpack-merge": "^5.7.3",
     "webpack-monitor": "^1.0.14"
   },
   "devDependencies": {