Fixed travis build, ready for tag

5.1.1 changelog

5.1.0 changelog

5.0.6 changelog

5.0.5 changelog

5.0.4 added pyproject.toml

5.0.3 changelog

fixed pytest version number so that tests work on python 3.7, and fil…

…led changelog 5.0.2

valid8 5.0.1 changelog with updated long description for pypi

fixed pytest version number in dependency to get doctest skip