[Checkins] [zopefoundation/DateTime] e472e1: setuptools-scm has not to be installed separately

[Michael Howitz]

  Branch: refs/heads/fix-travis
  Home:   https://github.com/zopefoundation/DateTime
  Commit: e472e18420c608d76aa699b029de53a9b63f5248
      https://github.com/zopefoundation/DateTime/commit/e472e18420c608d76aa699b029de53a9b63f5248
  Author: Michael Howitz <mac at gmx.net>
  Date:   2019-06-28 (Fri, 28 Jun 2019)

  Changed paths:
    M .travis.yml

  Log Message:
  -----------
  setuptools-scm has not to be installed separately

Using the PyPy version provided by xenial is enough.