Update pyproject.toml

[janvdp]

Additional PR for #684

Updated pyproject.toml to read the version dynamically following the setuptools docs: https://setuptools.pypa.io/en/latest/userguide/pyproject_config.html

[abetlen]

Hey @janvdp from version 0.2 on I started using the dynamic metadata regex tool from https://scikit-build-core.readthedocs.io/en/latest/configuration.html#dynamic-metadata to set the version which is now found in the root __init__.py file.

[janvdp]

@abetlen Aha, thanks for the info. I did not know. Had a look at the docs, found it a little obscure, but if it works, let's roll.

Safe to reject/delete this PR.