deprecation warning from pip

[pokeball99]

DEPRECATION: PyDispatcher is being installed using the legacy 'setup.py install' method, because it does not have a 'pyproject.toml' and the 'wheel' package is not installed. pip 23.1 will enforce this behaviour change. A possible replacement is to enable the '--use-pep517' option. Discussion can be found at pypa/pip#8559

[mcfletch]

I've updated the project with a pyproject.toml, which should, I believe, address the issue. Note that support for setuptools dynamic features is experimental, so we're depending on a beta feature to get around a deprecated feature, but oh well.