Warning about `"--global-option": ["--formats=gztar"]` emitted when using setuptools 64.0.1

[jwodder]

When using tox to build or install a setuptools-based package, if the tox-created virtualenv contains setuptools v64.0.1, then the following warning is emitted:

/Users/jwodder/work/pyproj/linesep/.tox/.package/lib/python3.9/site-packages/setuptools/build_meta.py:306: SetuptoolsDeprecationWarning:
            The arguments ['--formats=gztar'] were given via `--global-option`.
            Please use `--build-option` instead,
            `--global-option` is reserved to flags like `--verbose` or `--quiet`.

This appears to be due to this line of code in tox's source.

To Reproduce

1. Clone, say, https://github.com/jwodder/linesep
2. Ensure virtualenv uses the latest version of setuptools by running virtualenv --upgrade-embed-wheels
3. Run tox