Bump webpack-dev-server from 4.15.1 to 5.2.1 in /test/webpack

Bumps [webpack-dev-server](https://github.com/webpack/webpack-dev-server) from 4.15.1 to 5.2.1.
- [Release notes](https://github.com/webpack/webpack-dev-server/releases)
- [Changelog](https://github.com/webpack/webpack-dev-server/blob/master/CHANGELOG.md)
- [Commits](webpack/webpack-dev-server@v4.15.1...v5.2.1)

---
updated-dependencies:
- dependency-name: webpack-dev-server
  dependency-version: 5.2.1
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

test/webpack/package.json

@@ -9,6 +9,6 @@
   "devDependencies": {
     "webpack": "^5.89.0",
     "webpack-cli": "^5.1.4",
-    "webpack-dev-server": "^4.15.1"
+    "webpack-dev-server": "^5.2.1"
   }
 }