Follow-ups from #6

[cpu]

Couple quick follow-ups from https://github.com/dylanbstorey/pyo3-pylogger/pull/6:

• fix pyo3 version constraint - This should have been >=, not >, because 0.21 and 0.22 are compatible :)
• version 0.2.2 -> 0.3.0 - to match the GitHub release

[dylanbstorey]

Merged and released as 0.3.0 for real