www/py-django-filer: Update to 1.7.0

• Also assign the port to Django 2.2 because Django 1.11 is End-of-Life since April.

• Do the the same for its dependencies and bump PORTREVISION accordingly. [1] [2]

Changelog:

https://github.com/divio/django-filer/blob/1.7.0/CHANGELOG.rst

PR: 245470, 245472 [1] 245473 [2]
Approved by: maintainer timeout (14 days) [1],

		Kevin Golding (maintainer) [2]