Bump pystache from 0.6.6 to 0.6.7

Bumps [pystache](https://github.com/PennyDreadfulMTG/pystache) from 0.6.6 to 0.6.7.
- [Release notes](https://github.com/PennyDreadfulMTG/pystache/releases)
- [Changelog](https://github.com/PennyDreadfulMTG/pystache/blob/master/CHANGELOG.rst)
- [Commits](PennyDreadfulMTG/pystache@v0.6.6...v0.6.7)

---
updated-dependencies:
- dependency-name: pystache
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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