compatibility fix for Django 3

[kakulukia]

def upath(path):
    """Always return a unicode path (did something for Python 2)."""
    return path

I don't quite understand what it did anyway. :)

[Yattus]

Issue Incompatibility with Django early version:
ImportError: cannot import name 'upath' from 'django.utils._os' from app_namespace/loader.py, line 9
Alternative solution for me: Install django-apptemplates
Install link with pip : link