Bump cssnano from 7.0.6 to 7.1.1 (#3257)

Bumps [cssnano](https://github.com/cssnano/cssnano) from 7.0.6 to 7.1.1.
- [Release notes](https://github.com/cssnano/cssnano/releases)
- [Commits](https://github.com/cssnano/cssnano/compare/[email protected]@7.1.1)

---
updated-dependencies:
- dependency-name: cssnano
  dependency-version: 7.1.1
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]