Bump mixme from 0.5.1 to 0.5.4

Bumps [mixme](https://github.com/adaltas/node-mixme) from 0.5.1 to 0.5.4.
- [Release notes](https://github.com/adaltas/node-mixme/releases)
- [Changelog](https://github.com/adaltas/node-mixme/blob/master/CHANGELOG.md)
- [Commits](adaltas/node-mixme@v0.5.1...v0.5.4)

---
updated-dependencies:
- dependency-name: mixme
  dependency-type: indirect
...

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