[Checkins] [zopefoundation/zope.interface] 9dfaf5: MacOS wheels for 3.8

[Michael Howitz]

  Branch: refs/heads/icemac-patch-1
  Home:   https://github.com/zopefoundation/zope.interface
  Commit: 9dfaf533d881acc0a251ed065d18e3b4f621bf6d
      https://github.com/zopefoundation/zope.interface/commit/9dfaf533d881acc0a251ed065d18e3b4f621bf6d
  Author: Michael Howitz <mh at gocept.com>
  Date:   2020-03-12 (Thu, 12 Mar 2020)

  Changed paths:
    M .travis.yml

  Log Message:
  -----------
  MacOS wheels for 3.8

Copy-pasted from `persistent` as suggested by @mgedmin