textproc/py-zensical: Update to 0.0.15
Changelogs since 0.0.11:
https://github.com/zensical/zensical/releases/tag/v0.0.15
https://github.com/zensical/zensical/releases/tag/v0.0.14
https://github.com/zensical/zensical/releases/tag/v0.0.13
https://github.com/zensical/zensical/releases/tag/v0.0.12