feat: Replace flake8 and isort with ruff

[cclauss]

Thank you for contributing to Pipenv!

The issue

Continuation of #5361

Ruff supports over 500 lint rules and can be used to replace Flake8 (plus dozens of plugins), isort, pydocstyle, yesqa, eradicate, pyupgrade, and autoflake, all while executing (in Rust) tens or hundreds of times faster than any individual tool.

The fix

Added ruff in all the right places and removed flake8 and isort.

The checklist

• Associated issue
• A news fragment in the news/ directory to describe this fix with the extension .bugfix.rst, .feature.rst, .behavior.rst, .doc.rst. .vendor.rst. or .trivial.rst (this will appear in the release changelog). Use semantic line breaks and name the file after the issue number or the PR #.

[matteius]

Cool, I had not heard of ruff -- I assume because the test runner passed on windows that ruff works on windows too? I'm open to giving this a try.

[cclauss]

Yes. Ruff is installed by pipx or pip and is multiplatform.