[Checkins] [zopefoundation/martian] dca3df: Update changelog

[Marius Gedminas]

  Branch: refs/heads/fix-readonly-module-attribute
  Home:   https://github.com/zopefoundation/martian
  Commit: dca3df7ab30131b39a7e1412d2639eb7507675ec
      https://github.com/zopefoundation/martian/commit/dca3df7ab30131b39a7e1412d2639eb7507675ec
  Author: Marius Gedminas <marius at gedmin.as>
  Date:   2020-04-07 (Tue, 07 Apr 2020)

  Changed paths:
    M CHANGES.rst

  Log Message:
  -----------
  Update changelog