Bump cssnano from 4.1.11 to 6.0.1 (#1105)

Bumps [cssnano](https://github.com/cssnano/cssnano) from 4.1.11 to 6.0.1.
- [Release notes](https://github.com/cssnano/cssnano/releases)
- [Commits](https://github.com/cssnano/cssnano/compare/[email protected])

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

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: ghazal-salehi <[email protected]>
Co-authored-by: ghazal-salehi <[email protected]>