Bump webpack-dev-server from 3.9.0 to 3.11.2

Bumps [webpack-dev-server](https://github.com/webpack/webpack-dev-server) from 3.9.0 to 3.11.2.
- [Release notes](https://github.com/webpack/webpack-dev-server/releases)
- [Changelog](https://github.com/webpack/webpack-dev-server/blob/v3.11.2/CHANGELOG.md)
- [Commits](webpack/webpack-dev-server@v3.9.0...v3.11.2)

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

Author: dependabot-preview[bot]