v0.4.0

What's Changed

• Using importlib instead of pkg_resources for version number, bumped minimum required Python version to 3.9 by @tombch in #8
• Updated PyO3 from 0.17.3 to 0.24.2, specified minimum Python version as 3.9 by @tombch in #9
• Update maturin CI by @tombch in #10
• Development by @tombch in #11

Full Changelog: v0.3.0...v0.4.0