[Checkins] [zopefoundation/BTrees] caf710: build wheels for py3.8

[Forest Gregg]

  Branch: refs/heads/mac_py3.8_wheel
  Home:   https://github.com/zopefoundation/BTrees
  Commit: caf710248194aec5e45e08751c2aa0d2d994bb75
      https://github.com/zopefoundation/BTrees/commit/caf710248194aec5e45e08751c2aa0d2d994bb75
  Author: Forest Gregg <fgregg at uchicago.edu>
  Date:   2020-01-15 (Wed, 15 Jan 2020)

  Changed paths:
    M .travis.yml
    R appveyor.yml

  Log Message:
  -----------
  build wheels for py3.8