Replace hyphen with underscore to support setuptools setup.cfg

[afparsons]

Description

Currently, the setup.cfg file uses hyphens in fields. Setuptools 78.0.0 requires all fields to be formatted as lower_snake_case.

Given that this backwards-incompatible change broke many installations, Setuptools 78.0.2 temporarily suspends the deprecation until 2026.

This pull request updates setup.cfg to adhere to Setuptools' formatting requirements.

Checklist

• Wrote a description of my changes above
• Formatted my code with black
• Added a bullet point for my changes to the top of the CHANGELOG.md file
• Added or modified unit tests to reflect my changes
• Manually tested with a notebook
• If adding a feature, there is an example notebook and/or documentation in the README.md file