Bump webpack and karma-webpack

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

Updates `webpack` from 4.47.0 to 5.90.0
- [Release notes](https://github.com/webpack/webpack/releases)
- [Commits](webpack/webpack@v4.47.0...v5.90.0)

Updates `karma-webpack` from 4.0.2 to 5.0.0
- [Release notes](https://github.com/webpack-contrib/karma-webpack/releases)
- [Changelog](https://github.com/codymikol/karma-webpack/blob/master/CHANGELOG.md)
- [Commits](codymikol/karma-webpack@v4.0.2...v5.0.0)

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

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