Bump webpack-dev-middleware and webpack-dev-server

Bumps [webpack-dev-middleware](https://github.com/webpack/webpack-dev-middleware) and [webpack-dev-server](https://github.com/webpack/webpack-dev-server). These dependencies needed to be updated together.

Updates `webpack-dev-middleware` from 4.1.0 to 5.3.4
- [Release notes](https://github.com/webpack/webpack-dev-middleware/releases)
- [Changelog](https://github.com/webpack/webpack-dev-middleware/blob/v5.3.4/CHANGELOG.md)
- [Commits](webpack/webpack-dev-middleware@v4.1.0...v5.3.4)

Updates `webpack-dev-server` from 4.0.0-beta.2 to 4.15.2
- [Release notes](https://github.com/webpack/webpack-dev-server/releases)
- [Changelog](https://github.com/webpack/webpack-dev-server/blob/v4.15.2/CHANGELOG.md)
- [Commits](webpack/webpack-dev-server@v4.0.0-beta.2...v4.15.2)

---
updated-dependencies:
- dependency-name: webpack-dev-middleware
  dependency-type: indirect
- dependency-name: webpack-dev-server
  dependency-type: indirect
...

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

Author: dependabot[bot]