www/py-django-tagging: Update to 0.5.0

• Pet portclippy (sort variables according to the PHB) while I'm here.

Changelog:

https://github.com/Fantomas42/django-tagging/blob/v0.5.0/CHANGELOG.txt

PR: 245843
Submitted by: Kevin Golding <ports@caomhin.org> (maintainer)