[Checkins] [zopefoundation/zope.sendmail] 642747: Add support for Python 3.8.

[Michael Howitz]

  Branch: refs/heads/master
  Home:   https://github.com/zopefoundation/zope.sendmail
  Commit: 642747b244b4905f1bb0f75f00e3f250d3edee97
      https://github.com/zopefoundation/zope.sendmail/commit/642747b244b4905f1bb0f75f00e3f250d3edee97
  Author: Michael Howitz <mh at gocept.com>
  Date:   2019-04-03 (Wed, 03 Apr 2019)

  Changed paths:
    M .travis.yml
    M CHANGES.rst
    M setup.py
    M tox.ini

  Log Message:
  -----------
  Add support for Python 3.8.

Drop support for 3.4 as zope.testrunner no longer supports it.