Django-taxtea

Resolves issue with Django 3.1 checks failing with uncaught args.

- adds in a Django migration for the `help_text` added to TaxTea's models
- expands the python version support to >= 3.6

Initial Release of TaxTea

Features:

* Easy Tax Rate Calculation

* Support for Origin & Destination States

* Support for Tax Nexuses

* Integration with Avalara & USPS for up-to-date State/Zip & Tax Rate information

[Docs](https://www.djangotaxtea.com)