These macros allow projects that follow the Python packaging specifications
to be packaged as RPMs.
They work for:
* traditional Setuptools-based projects that use the setup.py file,
* newer Setuptools-based projects that have a setup.cfg file,
* general Python projects that use the PEP 517 pyproject.toml file
(which allows using any build system, such as setuptools, flit or poetry).
These macros replace %py3_build and %py3_install,
which only work with setup.py.
