textproc/py-pystache: Update to 0.6.8

• Update COMMENT
• Update WWW
• Convert to USE_PYTHON=pep517
• Update pkg-descr
• Take maintainership

Changes: https://github.com/PennyDreadfulMTG/pystache/releases

		https://github.com/PennyDreadfulMTG/pystache/blob/master/CHANGELOG.rst