Added support for python 3.8

• Added pyhton 3.8 support
• Removed support for django's versions below 2.2

Added Support for Django 2.2

Merge pull request #7 from edx/BOM-1026

Added the support for Django 2.2 - BOM-1026

Requirements Update

Updating the requirements, specifically jinja2, to counter security vulnerability present in the earlier versions of the dependency.