Make setup.py PEP517 compliant

[nico-von-huene]

Would fix #56

[bonlime]

@mattloper what's pending on merging this change? really small fix, that make it's easier to install chumpy

[gabmis]

@mattloper Hi! thanks for the nice package, this would help my team a lot, we often get errors when installing chumpy

[hectorpiteau]

@mattloper Hi! Is it possible to merge it? It would really help :)

[thearchitect]

You can pin commit from this PR and use this approach as a temporary solution if you are using pixi.
pixi.toml:

[pypi-dependencies]
chumpy = { git = "https://github.com/mattloper/chumpy.git", rev = "4228d703b622e172e843438fe0fada102979361a" }

[mlouielu]

If you are using uv:

uv add git+https://github.com/mattloper/chumpy.git --rev 4228d703b622e172e843438fe0fada102979361a