Bump yaml and htmlnano

Removes [yaml](https://github.com/eemeli/yaml). It's no longer used after updating ancestor dependency [htmlnano](https://github.com/posthtml/htmlnano). These dependencies need to be updated together.


Removes `yaml`

Updates `htmlnano` from 2.0.2 to 2.0.4
- [Release notes](https://github.com/posthtml/htmlnano/releases)
- [Changelog](https://github.com/posthtml/htmlnano/blob/master/CHANGELOG.md)
- [Commits](posthtml/htmlnano@2.0.2...2.0.4)

---
updated-dependencies:
- dependency-name: yaml
  dependency-type: indirect
- dependency-name: htmlnano
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>