Fix platform tag version regression for macOS 11 and later

[HexDecimal]

Zero out minor version of platform tags for macOS 11 and later which fixes the invalid tags for those releases. Closes #214

Delocate has a bias for testing older versions of macOS. I've added a test to ensure this works as intended.

Also discussed about in #214. This updates the behavior of MACOSX_DEPLOYMENT_TARGET and --require-target-macos-version. These will now raise the resulting platform tag versions if they are lower than the requested version. I'm certain this is desirable for MACOSX_DEPLOYMENT_TARGET but I'm not sure if it should be the same for --require-target-macos-version.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 96.99%. Comparing base (c93f910) to head (19b5121).
Report is 8 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #219      +/-   ##
==========================================
+ Coverage   96.94%   96.99%   +0.05%     
==========================================
  Files          16       16              
  Lines        1308     1333      +25     
==========================================
+ Hits         1268     1293      +25     
  Misses         40       40              

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[HexDecimal]

Multiple sections of code had mislabeled intel as universal. I didn't see any issues on this, possibly because those platforms are old. These have been fixed.

Only universal2 and intel are supported as combined architectures right now. In theory more can be supported but it's hard to find documentation on which architectures map to each other. The most I found for this would be in the packaging source code. For now universal2 seems to be the only one being used publicly.

I've decided to deprecate --require-target-macos-version since it causes confusion with MACOSX_DEPLOYMENT_TARGET. From now on all instructions should only mention MACOSX_DEPLOYMENT_TARGET.