[Checkins] [zopefoundation/Zope] 18c406: Update to current versions

[GitHub]

  Branch: refs/heads/2.13
  Home:   https://github.com/zopefoundation/Zope
  Commit: 18c406ecdb4323678f54645c6a68e5ffe7aa56a4
      https://github.com/zopefoundation/Zope/commit/18c406ecdb4323678f54645c6a68e5ffe7aa56a4
  Author: Michael Howitz <mh at gocept.com>
  Date:   2017-09-25 (Mon, 25 Sep 2017)

  Changed paths:
    M doc/INSTALL-virtualenv.rst

  Log Message:
  -----------
  Update to current versions