Migrate to pyproject.toml for project configuration

[crazy4pi314]

Pre-Request Checklist

• [x] I checked to make sure that this feature has not already been requested.

Issue Description

By newly accepted PEP guides for best practices, project configuration/parameters should be set in a pyproject.toml instead of requirements files, setup.py, and other conf files. Many other tools in the Python ecosystem already support getting configuration from these toml files (just another markdown sort of syntax). One really nice thing about this is that there is one file (not script) that you can look at for everything you need to configure the project. It allows for so many specifications like optional and dev dependencies, easy version numbering based on git tags, and so much more.

Proposed Solution

Move any tools/configuration to the pyproject.toml file we already have (black requires it for conf).

Tools confirmed to use:

• black
• pytest
• mypy

Tools that we use that don't default support pyproject.toml, but have shims to make it work:

• flake8
• sphinx
  • MyST by extension

Additional References

Blogs from Python core maintainers/community that are helpful in understanding the changes and how to migrate:

• https://snarky.ca/what-the-heck-is-pyproject-toml/
• http://ivory.idyll.org/blog/2021-transition-to-pyproject.toml-example.html
• https://discuss.python.org/t/where-to-get-started-with-pyproject-toml/4906

Examples of files in the wild:

• https://github.com/sphinx-toolbox/sphinx-pyproject/blob/master/pyproject.toml

[dbanty]

@crazy4pi314 will you be using Poetry to define dependencies as part of this? It’ll give you the separation between ranges on install and pinning for CI that you’re looking for in #839 and is by far the easiest way to manage dependencies in general (that I’ve found).

We use it over in pyQuil if you want to see an example of config, usage in CI, etc.

[crazy4pi314]

@crazy4pi314 will you be using Poetry to define dependencies as part of this?

Yeah, I think that would make the most sense. It is just too complicated to manage the different groups of requirements, lockfiles, and package metadata it seems without tools like Poetry :) Thanks for the example too!

[github-actions[bot]]

This issue had no activity for 2 months, and will be closed in one week unless there is new activity. Cheers!

[natestemen]

related: https://github.com/unitaryfund/mitiq/issues/857