PEP621: Move more configuration into pyproject.toml

[cclauss]

Purpose

Describe the problem or feature in addition to a link to the issues.
Related to the discussion in #256

Use ini2toml to migrate more configuration to pyproject.toml and run validate-pyproject to validate results.

• Currently flake8 is not yet compatible with pyproject.toml so move its config to .flake8

Approach

How does this change address the problem?
% ini2toml setup.cfg | pbcopy
% code pyproject.toml setup.cfg
% git mv setup.cfg .flake8
% validate-pyproject pyproject.toml

Valid file: pyproject.toml

Open Questions and Pre-Merge TODOs

• Use GitHub checklists. When solved, check the box and explain the answer.

Resources & Links

Links to blog posts, patterns, libraries or add-ons used to solve this problem

[abravalheri]

Thank you very much @cclauss, I rebased this one on top of the latest changes.

[abravalheri]

I am also changing the target to the dev branch.

We can start preparing for the v6 version on the dev branch which should be focused in the latest pyproject.toml experience.

I have to admit I am very delayed with that 😝, still have to find the time to implement the other required changes...

[coveralls]

Coverage: 97.78%. Remained the same when pulling b3cbba5 on cclauss:PEP621-more-pyproject.toml into c0a5f97 on pyscaffold:dev.

[cclauss]

Impressive!

[abravalheri]

I merged this into dev, officially starting the works on v6 (hopefully I will have some time to dedicate to that).