Remove universal wheel creation from setup.cfg files

[IAlibay]

Easy enough one whilst I'm making Saturday night dinner

We need to drop the creation of universal wheels because a) we have C extension, b) we don't support py2 anymore.

see: https://packaging.python.org/en/latest/guides/distributing-packages-using-setuptools/#wheels

Note: as far as I'm aware there's no [wheel] entry anyways, it should be [bdist_wheel], but it does get interpreted by setuptools as the same. Removing the entry changes the generated wheel from MDAnalysisTests-2.3.0.dev0-py2.py3-none-any.whl to MDAnalysisTests-2.3.0.dev0-py3-none-any.whl which is what we're looking for

In practice we don't create them anyways, but we can see from conda-forge that there is an attempt at creating them as part of the package build.

Changes made in this Pull Request:

• Remove

PR Checklist

• Tests?
• Docs?
• CHANGELOG updated?
• Issue raised/referenced?

[codecov]

Codecov Report

Merging #3763 (96d539e) into develop (d5c7cb9) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##           develop    #3763   +/-   ##
========================================
  Coverage    94.31%   94.31%           
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  Files          192      192           
  Lines        24752    24752           
  Branches      3338     3338           
========================================
  Hits         23345    23345           
  Misses        1359     1359           
  Partials        48       48           

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