Clean up install vs. build requirements

[jwilges]

Summary

Clean up install vs. build requirements

• Exclude wheel and setuptools from package dependencies
• Exclude packaging from build dependencies; however, retain it as a package dependency since it is a valid runtime dependency

Issue

When downstream packages depend on mgrs today, they have wheel forced into their dependency graphs at install time. This occurs because mgrs as the upstream package currently lists two of its build requirements--wheel and setuptools--as install requirements. To clean this up, we can keep wheel and setuptools as valid build system requirements in pyproject.toml, but we should omit them from setup.py's install_requires section.

[jwilges]

@hobu let me know if you have any issues with this, but if not, it would be seriously awesome to get this merged and pushed as a newer release on PyPI so we can update our downstream references and shake wheel out of our dependency graphs.

[jwilges]

You might win the open source hero award for fastest maintainer @hobu... Much love from the PNW, my friend!

I'm working on fixing our dependencies and this one was throwing us for a loop so I wanted to contribute the fix for all to enjoy. I'll keep an eye out for the PyPI version bump once you get a chance to release!

[hobu]

github actions borked right now, but when it catches up to the queue, the release will be pushed to PyPI.

[jwilges]

Thanks @hobu, it's really appreciated!