build(deps-dev): bump webpack-dev-server in /frontend

Bumps [webpack-dev-server](https://github.com/webpack/webpack-dev-server) from 4.1.1 to 4.7.3.
- [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@v4.1.1...v4.7.3)

---
updated-dependencies:
- dependency-name: webpack-dev-server
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]