Bump optimize-css-assets-webpack-plugin from 5.0.8 to 6.0.1

Bumps [optimize-css-assets-webpack-plugin](https://github.com/NMFR/optimize-css-assets-webpack-plugin) from 5.0.8 to 6.0.1.
- [Commits](NMFR/optimize-css-assets-webpack-plugin@v5.0.8...v6.0.1)

---
updated-dependencies:
- dependency-name: optimize-css-assets-webpack-plugin
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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