[Checkins] [zopefoundation/zope.testrunner] a8d1c9: Try out Python 3.9

[Michael Howitz]

  Branch: refs/heads/try-py3.9
  Home:   https://github.com/zopefoundation/zope.testrunner
  Commit: a8d1c9355a71e7ce0be7a03f2918ea9974055084
      https://github.com/zopefoundation/zope.testrunner/commit/a8d1c9355a71e7ce0be7a03f2918ea9974055084
  Author: Michael Howitz <mh at gocept.com>
  Date:   2020-06-29 (Mon, 29 Jun 2020)

  Changed paths:
    M .travis.yml

  Log Message:
  -----------
  Try out Python 3.9

In ZTK tests it breaks.