modernized build

[mgor]

i mentioned in a previous PR #2040 that there was problems adding locust as a git dependency; pip or pip-tools got confused that there was a pyproject.toml, but no build-system section available. all it contained was settings for black.

there have been other projects having the same problem.

the underlying problem seems to have been fixed now, so it is indeed possible to have locust as a git dependency (which I realized after implementing this...). but there are probably other benefits of moderizing the build setup to be PEP517 and PEP518 compatible.

since most stuff already was present in setup.cfg, it was quite an easy transition to move away from setup.py, however editable installs is not yet supported by pyproject.toml and hence a bare bone setup.py is needed.

most work had to be done in the github workflow and tox settings.

regarding the changes of command to python -m <module> in test.yml:
https://snarky.ca/why-you-should-use-python-m-pip/

[mgor]

i was unable to get it working with pywin32 being an extras_require as in the setup.py case, however this should be the same(?). pywin32 only needed when running on windows.
https://setuptools.pypa.io/en/latest/userguide/dependency_management.html#platform-specific-dependencies

[cyberw]

LGTM. Have you tested it on windows? I have a windows box somewhere, but I can't be bothered to fire it up :)

[mgor]

LGTM. Have you tested it on windows? I have a windows box somewhere, but I can't be bothered to fire it up :)

If you mean the changed way pywin32 is included?

I could've actually just tested it myself.. without writing an obscure comment like that, my bad.

on "linux" (Windows 10 WSL2 with ubuntu 21.04):

➜ pip install .
➜ pip freeze | grep pywin32
➜ 

on windows 10:

(locust-venv) C:\NoBackup\locust [feature/pep_517_518 ≡]> pip3 install .
(locust-venv) C:\NoBackup\locust [feature/pep_517_518 ≡]> pip3 freeze | Select-String pywin32

pywin32==303

[cyberw]

I’m gonna give Heyman a day or two to chime in, but it looks all good to me!

[heyman]

Looks good to me 👍