Stop building universal wheels

[tucked]

Resolve #5496

https://packaging.python.org/en/latest/guides/dropping-older-python-versions/#dealing-with-the-universal-wheels

Traditionally, projects providing Python code that is semantically compatible with both Python 2 and Python 3, produce wheels that have a py2.py3 tag in their names. When dropping support for Python 2, it is important not to forget to change this tag to just py3. It is often configured within setup.cfg under the [bdist_wheel] section by setting universal = 1 if they use setuptools.

The checklist

• Associated issue
• A news fragment in the news/ directory to describe this fix with the extension .bugfix.rst, .feature.rst, .behavior.rst, .doc.rst. .vendor.rst. or .trivial.rst (this will appear in the release changelog). Use semantic line breaks and name the file after the issue number or the PR #.

[tucked]

FWIW, "Squash and Merge" discards commit signatures:

becomes

[matteius]

Sorry about that, it's my default but definitely did not need to be squashed on your PR.

[tucked]

No worries, it's NBD... Just thought I'd mention it since most people aren't aware of it 😊