Changelog compatibility Python library

Version 1.0.1 stable (2021-08-05)

Marked as compatible with Python 3.10 as tests with release candidate 1 run flawlessly on Linux, MacOS, and Windows.

New feature: the parameter system_support allows you to state the level of compatibility between your code and different Operating System groups. This is purposefully done on a very high level: valid inputs are only 'Linux', 'MacOS', and 'Windows' and not specific versions and distributions. The dictionary allows three keys with a set as value each:
- full: The set of operating systems that are tested on production level.
- partial: The set of systems that should work, but are not as rigorously tested as those with full support. A system running found here logs a warning.
- incompatible: The set of systems of which you know they will fail to run the code properly. If an OS in this set tries to run the code, this will yield a RuntimeError exception.
Tests now also run with the third beta version of the upcoming Python 3.10.
Although the code should be completely platform independent, tests are now also run on MacOS and Windows.

Change development status from beta to stable.
The parameter release_date now also accepts a string in the format YYYY-MM-DD besides a datetime object.

Initial public release. Chose a high version number to indicate it is almost feature complete and has a high test coverage.