Replace django.utils.encoding.smart_text usage with smart_str
Replace django.utils.encoding.smart_text usage with smart_str

smart_text is deprecated in favor of smart_str.

https://docs.djangoproject.com/en/3.1/releases/3.0/#django-utils-encoding-force-text-and-smart-text

City-of-Helsinki/django-helusers,City-of-Helsinki/django-helusers