Fix setuptools_scm configuration

[asvetlov]

pyproject.toml should use setuptools_scm[toml] dependency.
In turn, bare setuptools_scm should be dropped from setup.cfg setup_requires section.

@webknjaz suggested the change for another aio-libs project.

[asvetlov]

Interesting, tests are failed.
@webknjaz could you please take a look at what is wrong with the PR?
Should setup_requires = setuptools_scm>=6.2 be used for the project?

[seifertm]

We encountered the same issue in the PR where we integrated setuptools_scm. I had a theory why this is happening, but I'm not 100% sure. Cross-reference: #37 (comment)

[webknjaz]

Should setup_requires = setuptools_scm>=6.2 be used for the project?

This shouldn't be necessary. I can't check right now but my immediate guess would be to check pip/setuptools versions. I'll try to get back to this once I can look at it from my laptop.

[webknjaz]

Oh, I see what's happening:

ERROR: FAIL could not package project - v = InvocationError('/opt/hostedtoolcache/Python/3.7.12/x64/bin/python setup.py sdist --formats=zip --dist-dir /home/runner/work/pytest-asyncio/pytest-asyncio/.tox/dist', 1)

Tox invokes setup.py directly and PEP517 is never used. Enable build isolation to fix this.

[seifertm]

Thanks @webknjaz, good find! Enabling build isolation did the trick: The dependency on setuptools_scm in pyproject.toml is now recognized correctly.

[seifertm]

@asvetlov I hope you don't mind I took this PR over :)

[webknjaz]

good find!

It would've been discovered earlier if setup.py was deleted (which I recommend — there's no legitimate reason for keeping it anymore).