Enabled Python 3.8 Support & Docs

[nachomaiz]

Description

bavapi has been updated to be able to run in Python 3.8.

Python support will now follow PSF release and support schedule. https://devguide.python.org/versions/

Documentation has been refreshed.

Motivation and Context

• Changed all uses of list, dict, set and type in type hints for Python 3.8-compatible List, Dict, Set and Type.
• Changed code to avoid updating dictionaries with the union operator |, introduced in Python 3.9.
• Docstring improvements.

How Has This Been Tested?

The full test suite has been run, as well as mypy and pylint.

Checklist

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added the changelog accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[nachomaiz]

All good!