[Checkins] [zopefoundation/AccessControl] b84fd2: Add required package.

[Michael Howitz]

  Branch: refs/heads/fix-81
  Home:   https://github.com/zopefoundation/AccessControl
  Commit: b84fd278e9bd3bc09db9afc2833482cf7f0293e4
      https://github.com/zopefoundation/AccessControl/commit/b84fd278e9bd3bc09db9afc2833482cf7f0293e4
  Author: Michael Howitz <mh at gocept.com>
  Date:   2019-05-08 (Wed, 08 May 2019)

  Changed paths:
    M appveyor.yml

  Log Message:
  -----------
  Add required package.