With setup tools v78, using hyphens for fields in `setup.cfg` has been [deprecated](https://setuptools.pypa.io/en/latest/history.html#v78-0-0). Although v78.0.2 has [postponed breaking changes](https://setuptools.pypa.io/en/latest/history.html#v78-0-0), the warning has apparently [been in place since v54.1.0](https://setuptools.pypa.io/en/latest/history.html#id857) in 2021. See e.g. https://github.com/pypa/setuptools/issues/4910