[Checkins] [zopefoundation/Persistence] d692e2: Update to persistent >= 4.2.3. (#9)

[GitHub]

  Branch: refs/heads/master
  Home:   https://github.com/zopefoundation/Persistence
  Commit: d692e20f27e76ed8c7a7defb975f4ea38a91ed9a
      https://github.com/zopefoundation/Persistence/commit/d692e20f27e76ed8c7a7defb975f4ea38a91ed9a
  Author: Michael Howitz <mh at gocept.com>
  Date:   2018-02-02 (Fri, 02 Feb 2018)

  Changed paths:
    M CHANGES.rst
    M src/Persistence/tests/test_persistent.py
    M tox.ini

  Log Message:
  -----------
  Update to persistent >= 4.2.3. (#9)

* Update to persistent >= 4.2.3.

* Use the version of `PickleCache` matching the used `persistent` variant.