[Checkins] [zopefoundation/Zope] b2b1f1: Add --pack as suggested by docs of zodbupdate

[Michael Howitz]

  Branch: refs/heads/icemac-patch-1
  Home:   https://github.com/zopefoundation/Zope
  Commit: b2b1f10eb21a3f71fede3fb02190eca74854c195
      https://github.com/zopefoundation/Zope/commit/b2b1f10eb21a3f71fede3fb02190eca74854c195
  Author: Michael Howitz <mh at gocept.com>
  Date:   2019-06-26 (Wed, 26 Jun 2019)

  Changed paths:
    M docs/zope4/migration/zodb.rst

  Log Message:
  -----------
  Add --pack as suggested by docs of zodbupdate

[skip ci]