chore(deps-dev): bump webpack-dev-server from 2.11.5 to 5.2.1 in /studio

Bumps [webpack-dev-server](https://github.com/webpack/webpack-dev-server) from 2.11.5 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](https://github.com/webpack/webpack-dev-server/commits/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]

studio/package.json

@@ -101,7 +101,7 @@
     "typescript": "^2.9.2",
     "url-loader": "^0.5.7",
     "webpack": "2.7.0",
-    "webpack-dev-server": "2.11.5"
+    "webpack-dev-server": "5.2.1"
   },
   "engines": {
     "node": ">=0.8.0"