Bump open and webpack-dev-server

Bumps [open](https://github.com/sindresorhus/open) to 8.4.2 and updates ancestor dependency [webpack-dev-server](https://github.com/webpack/webpack-dev-server). These dependencies need to be updated together.


Updates `open` from 0.0.5 to 8.4.2
- [Release notes](https://github.com/sindresorhus/open/releases)
- [Commits](https://github.com/sindresorhus/open/commits/v8.4.2)

Updates `webpack-dev-server` from 1.16.5 to 4.13.3
- [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@v1.16.5...v4.13.3)

---
updated-dependencies:
- dependency-name: open
  dependency-type: indirect
- dependency-name: webpack-dev-server
  dependency-type: direct:development
...

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

Author: dependabot[bot]