[Checkins] [zopefoundation/Products.MailHost] b9d50a: Supported Python version cleanup

[Jens Vagelpohl]

  Branch: refs/heads/master
  Home:   https://github.com/zopefoundation/Products.MailHost
  Commit: b9d50a4a23f75e29eeea7093ad0db11ae7079438
      https://github.com/zopefoundation/Products.MailHost/commit/b9d50a4a23f75e29eeea7093ad0db11ae7079438
  Author: Jens Vagelpohl <jens at netz.ooo>
  Date:   2019-02-17 (Sun, 17 Feb 2019)

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

  Log Message:
  -----------
  Supported Python version cleanup

- specify supported Python versions using ``python_requires`` in setup.py
- added support for Python 3.8