update pyproject.toml for conda-forge recipe

[rosepearson]

Plan to build the recipe directly from this GitHub repository using grayskull. *

• Note for loading the version from the pyproject.toml - https://stackoverflow.com/questions/71412385/can-python-snippets-be-placed-in-pyproject-toml - looks like this requires python 3.8: https://stackoverflow.com/questions/67085041/how-to-specify-version-in-only-one-place-when-using-pyproject-toml

[rosepearson]

Note tidy packaging based on: https://github.com/jennan/my_little_package

Thanks @jennan for the example

[rosepearson]

Have made some updates. Not GeoFabrics already published on Conda-Forge: https://anaconda.org/conda-forge/geofabrics