Drop support for outdated python and gevent versions

[ml31415]

@cyberw please have a look. Should be good for now.

• Dropping support for python < 3.9 and gevent < 1.0
• Fixes Drop python2 support #190
• Removed python2 syntax and version forks
• Added pyproject.toml

[cyberw]

Ooh, that was a very quick merge :)

Can I ask for a few more things: the pure formatting changes to be added to a git-blame ignore file, like this: https://github.com/locustio/locust/blob/master/.git-blame-ignore-revs
(so they dont ”pollute” the git-blame)

Did you run pyupgrade? If not, try it and see what changes it suggests.

[cyberw]

Do you really want fix = false in pyproject.toml? Dont you just want to add the --check flag when ruff is run by tox?

[ml31415]

So far I was using ruff format as a replacement for black and ruff check --fix --select I as a replacement of isort.

About fix = false: Yes. Mainly because I've seen ruff messing up stuff, if it thinks it knows, what's going on and that wasn't the case, so I'm a bit afraid of too much auto fixing, that exceeds plain formatting. Not sure, ruff is quickly developing, totally fine with changing this at some point. But as long as we don't enforce any pre-commit runs, it doesn't matter too much anyways, I guess.

About the ignore-refs, yeah, in hindsight it was quite stupid to do a squash commit with all that changes together :/ Are you fine with putting the whole squashed commit hash into the ignore list? Otherwise, I guess we need to redo the whole merge.

[cyberw]

Regarding blame, I didnt see that you squashed as well. Never mind then, definitely not worth redoing anything for that.

I've found ruff very stable. Can you add it to tox? Ideally as a separate env (like here https://github.com/locustio/locust/blob/a7ca357ca15e10bc77b4bc3b0dd96548c84f7d9f/tox.ini#L34) but because it is so fast we could just run it for every python version (if that is easier for you to do). Adding a pre-commit hook would be even nicer, but that can be step 2.