Bumps [html-minifier](https://github.com/kangax/html-minifier) from 3.5.6 to 3.5.7.
- [Release notes](https://github.com/kangax/html-minifier/releases/tag/v3.5.7)
- [Commits](https://github.com/kangax/html-minifier/compare/v3.5.6...v3.5.7)