www/py-django-auth-ldap: Update to 2.0.0

• Take maintainership due three consecutive maintainer timeouts
• Limit to Python 3.5 and later as upstream has dropped the support for Python 2 and 3.4

Changelog:

https://github.com/django-auth-ldap/django-auth-ldap/blob/2.0.0/CHANGES

PR: 238359
Approved by: maintainer timeout