chore(deps-dev): bump webpack-dev-server in /sites/upsun

Bumps [webpack-dev-server](https://github.com/webpack/webpack-dev-server) from 5.2.1 to 5.2.5.
- [Release notes](https://github.com/webpack/webpack-dev-server/releases)
- [Changelog](https://github.com/webpack/webpack-dev-server/blob/main/CHANGELOG.md)
- [Commits](webpack/webpack-dev-server@v5.2.1...v5.2.5)

---
updated-dependencies:
- dependency-name: webpack-dev-server
  dependency-version: 5.2.5
  dependency-type: direct:development
...

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Author: dependabot[bot]