[Checkins] [zopefoundation/z3c.authenticator] 7e54f0: Add Python 3.7 support

[Marius Gedminas]

  Branch: refs/heads/drop-py26-srsly
  Home:   https://github.com/zopefoundation/z3c.authenticator
  Commit: 7e54f05f294e6bb0cd97d6fe2bc7a14ae4ab022a
      https://github.com/zopefoundation/z3c.authenticator/commit/7e54f05f294e6bb0cd97d6fe2bc7a14ae4ab022a
  Author: Marius Gedminas <marius at gedmin.as>
  Date:   2019-04-25 (Thu, 25 Apr 2019)

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

  Log Message:
  -----------
  Add Python 3.7 support

Also drop Python 2.6 from .travis.yml.