Healpix-alchemy

- Don't include the unit tests in the installed Python package.

- Drop support for Python 3.9. Add support for, and run unit tests for,
Python 3.12.

- Update build system for compatibility with the latest version of Poetry.

- Track API changes in mocpy.

- Fix compatibility with SQLAlchemy 2.x.

- Add benchmarks to unit test suite.

- Update the doctest examples in the README file to match the paper draft.

- Add code coverage analysis with Codecov.io.

- First stable release.