Replace request.user.is_authenticated() by request.user.is_authenticated (Django 3)

[fmoralesalcaide]

The method version is deprecated in Django 3.x. Replacing it by the attribute version makes the module work. I understand that the project is not mantained anymore, but this is the only change that I need in order to work.

Could you please review these changes and upload them to pypi?

[coveralls]

Coverage remained the same at 100.0% when pulling f197f1f on fmoralesalcaide:is_authenticated_attribute_fix into 7e5a4ad on 2degrees:master.

[coveralls]

Coverage remained the same at 100.0% when pulling f197f1f on fmoralesalcaide:is_authenticated_attribute_fix into 7e5a4ad on 2degrees:master.

[franciscoruiz]

Hi @fmoralesalcaide
I'll take a look at the failures in Travis over the weekend, and will try to progress this ASAP.

[traverseda]

Seconding this, let me know if there's anything I can do to help.