Add a changelog for PyPI

[aliceinwire]

PyPI can use changelog files for show to pypi website what as been changed on new releases

[aliceinwire]

https://packaging.python.org/en/latest/guides/writing-pyproject-toml/#urls

[aliceinwire]

https://packaging.python.org/en/latest/specifications/well-known-project-urls/#well-known-labels

[aliceinwire]

#78
using the release link as changelog