Can't test with Python 3.10-beta.3

[thedrow]

It seems like tox-gh-actions has a problem parsing these type of Python versions.
See build log.

[ymyzk]

This format 3.10-beta.3 is not supported by tox-gh-actions. Please simply specify 3.10 instead.

[gh-actions]
python =
    3.6: 3.6-unit
    3.7: 3.7-unit
    3.8: 3.8-unit
    3.9: 3.9-unit
    3.10: 3.10-unit
    pypy3: pypy3-unit

[thedrow]

That works. Thanks!