Update requirements for django
Update requirements for django

Update requirements.txt to allow any Django 2.2 or 3.x release
gwasser/django-helpdesk,rossp/django-helpdesk,django-helpdesk/django-helpdesk,gwasser/django-helpdesk,django-helpdesk/django-helpdesk,rossp/django-helpdesk,gwasser/django-helpdesk,rossp/django-helpdesk,gwasser/django-helpdesk,django-helpdesk/django-helpdesk,django-helpdesk/django-helpdesk,rossp/django-helpdesk