Remove redundant wheel dep from pyproject.toml

[mgorny]

Remove the redundant wheel dependency, as it is added by the backend
automatically. Listing it explicitly in the documentation was
a historical mistake and has been fixed since, see:
pypa/setuptools@f7d30a9

[cpburnz]

Thanks for fixing this.

[mgorny]

Thanks! Could you tell me where did that wheel dep come from? I'm trying to fix all the obsolete docs but not sure where it is still listed.

[cpburnz]

I included the wheel dependency to be safe because it was inconsistently used. I've been looking into pyproject.toml in passing for the past half year. In particular, I still see it at:

• https://peps.python.org/pep-0518/
• https://pip.pypa.io/en/stable/reference/build-system/pyproject-toml/#fallback-behaviour
• https://github.com/pypa/pip/blob/main/pyproject.toml
• Document setuptools.build_meta pypa/setuptools#1698

The documentation for pyproject.toml is getting better but I still contend it is a mess. The PEPs are completely useless because you don't know what is actually supported. The only useful piece of documentation I've found is Configuring setuptools using pyproject.toml files which is relatively recent, and digging into what other projects do.