[Checkins] [zopefoundation/z3c.checkversions] 6ec795: Use subprocess.check_output() in test

[Marius Gedminas]

  Branch: refs/heads/fix-resource-warnings
  Home:   https://github.com/zopefoundation/z3c.checkversions
  Commit: 6ec795138a9aae7f800b740a5fc7d20764071770
      https://github.com/zopefoundation/z3c.checkversions/commit/6ec795138a9aae7f800b740a5fc7d20764071770
  Author: Marius Gedminas <marius at gedmin.as>
  Date:   2019-10-20 (Sun, 20 Oct 2019)

  Changed paths:
    M src/z3c/checkversions/buildout.txt

  Log Message:
  -----------
  Use subprocess.check_output() in test

Because this makes the code simpler.

Co-authored-by: Jason Madden <jason at nextthought.com>