chore(deps-dev): bump webpack-dev-server from 3.11.2 to 4.15.1

Bumps [webpack-dev-server](https://github.com/webpack/webpack-dev-server) from 3.11.2 to 4.15.1.
- [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@v3.11.2...v4.15.1)

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

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

package.json

@@ -101,7 +101,7 @@
  "webpack": "^4.39.2",
  "webpack-cli": "^4.7.0",
  "webpack-dev-middleware": "^5.0.0",
- "webpack-dev-server": "^3.8.0",
+ "webpack-dev-server": "^4.15.1",
  "webpack-hot-middleware": "^2.25.0"
  },
  "peerDependencies": {