[Checkins] [zopefoundation/DateTime] f24132: Upgrade to xenial maybe fixes PyPy on Travis.

[Michael Howitz]

  Branch: refs/heads/fix-travis
  Home:   https://github.com/zopefoundation/DateTime
  Commit: f241325de762f5b9f58bbd5c8faa4c1812e94b31
      https://github.com/zopefoundation/DateTime/commit/f241325de762f5b9f58bbd5c8faa4c1812e94b31
  Author: Michael Howitz <mac at gmx.net>
  Date:   2019-06-28 (Fri, 28 Jun 2019)

  Changed paths:
    M .travis.yml

  Log Message:
  -----------
  Upgrade to xenial maybe fixes PyPy on Travis.