[MRG] Migrate to pyproject.toml

[aaronreidsmith]

Description

pip 23.1 drops support for setup.py being called directly (python setup.py), so we have to adapt by adding a pyproject.toml as an entrypoint. I am using setuptools.build_meta:__legacy__ as the build backend because it is the most similar to what we have today. Eventually we'll want to move to something else setuptools.build_meta, meson, etc.). I ran into problems trying to do those directly because they don't allow partial imports of pmdarima during the build process.

Separately, distutils (and by extension numpy.distutils) is deprecated and being removed in Pytohn 3.12+. We need to look into how to replace that...

Type of change

• [X] Build change

How Has This Been Tested?

• [X] Builds pass

Checklist:

• [X] I have performed a self-review of my own code
• [X] I have commented my code, particularly in hard-to-understand areas
• [X] I have made corresponding changes to the documentation
• [X] My changes generate no new warnings
• [X] I have added tests that prove my fix is effective or that my feature works
• [X] New and existing unit tests pass locally with my changes

[aaronreidsmith]

Separately, distutils (and by extension numpy.distutils) is deprecated and being removed in Pytohn 3.12+. We need to look into how to replace that...

Looks like we can use setuputils.command.build_ext as a drop-in replacement. I might try that on this branch