move build configuration to pyproject.toml

[zacharyburnett]

setuptools now supports the [project] table, which is defined by PEP621.

Additionally, setuptools now supports its own entry in pyproject.toml called [tool.setuptools] (pypa/setuptools#1688, https://setuptools.pypa.io/en/latest/userguide/pyproject_config.html#setuptools-specific-configuration); however, it comes with the following disclaimer:

Support for declaring configurations not standardized by PEP 621 (i.e. the [tool.setuptools] table), is still in beta stage and might change in future releases.

Reading toml is supported natively in Python 3.11 with tomllib

Given this, we can attempt to consolidate the build configuration into a single pyproject.toml file that can possibly be read by other build systems in the future.

[nden]

LGTM.
Just need to remove the python 3.8 test from ci.yaml.

[zacharyburnett]

thanks!