Refactor from setup to pyproject.toml

[prjemian]

While working on PR #7, this was reported in the CI:

2024-02-08T05:40:10.5804752Z   /tmp/pip-build-env-4ym2k1aw/overlay/local/lib/python3.10/dist-packages/setuptools_scm/_integration/setuptools.py:30: RuntimeWarning:
2024-02-08T05:40:10.5807135Z   ERROR: setuptools==59.6.0 is used in combination with setuptools_scm>=8.x
2024-02-08T05:40:10.5808342Z 
2024-02-08T05:40:10.5809770Z   Your build configuration is incomplete and previously worked by accident!
2024-02-08T05:40:10.5811379Z   setuptools_scm requires setuptools>=61
2024-02-08T05:40:10.5812417Z 
2024-02-08T05:40:10.5814098Z   Suggested workaround if applicable:
2024-02-08T05:40:10.5816522Z    - migrating from the deprecated setup_requires mechanism to pep517/518
2024-02-08T05:40:10.5817706Z      and using a pyproject.toml to declare build dependencies
2024-02-08T05:40:10.5819251Z      which are reliably pre-installed before running the build tools