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: https://github.com/pypa/setuptools/commit/f7d30a9529378cf69054b5176249e5457aaf640a

[mgorny]

Thank you!