Bump cerdic/css-tidy from 1.5.7 to 1.6.5

Bumps [cerdic/css-tidy](https://github.com/Cerdic/CSSTidy) from 1.5.7 to 1.6.5.
- [Release notes](https://github.com/Cerdic/CSSTidy/releases)
- [Changelog](https://github.com/Cerdic/CSSTidy/blob/master/NEWS)
- [Commits](https://github.com/Cerdic/CSSTidy/compare/v1.5.7...v1.6.5

)

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