From the setuptools documentation (68.0.0):

Starting with PEP 621, the Python community selected pyproject.toml as a standard way of specifying project metadata. Setuptools has adopted this standard and will use the information contained in this file as an input in the build process.

PyPa also recommends pyproject.toml. The canonical spec is found here: declaring project metadata

Wouldn't it be a good idea to move the workbench_starterkit metadata from setup.py to pyproject.toml as well?

Seems important to stay up to date here, especially since this is going to be a starting point for new package development.