Update install documentation to use re_path (#6613)
Update install documentation to use re_path (#6613)

* Update install documentation to use re_path 

The example with url(...) no longer works. The correct syntax is re_path(...).

* Changed documentation to based on feedback from Bartosz Płóciennik

The change to use re_path is only necessary when using Django 2.0. Reverted the change and added a note for Django 2.0 users.

divio/django-cms,datakortet/django-cms,divio/django-cms,yakky/django-cms,yakky/django-cms,datakortet/django-cms,yakky/django-cms,benzkji/django-cms,rsalmaso/django-cms,rsalmaso/django-cms,rsalmaso/django-cms,divio/django-cms,benzkji/django-cms,datakortet/django-cms,yakky/django-cms,rsalmaso/django-cms,divio/django-cms,benzkji/django-cms,benzkji/django-cms,datakortet/django-cms