[logback-dev] [qos-ch/logback] caafc0: Update CONTRIBUTING.md

[Tony Trinh]

  Branch: refs/heads/master
  Home:   https://github.com/qos-ch/logback
  Commit: caafc05a097c7f454e693bb971334703e287168b
      https://github.com/qos-ch/logback/commit/caafc05a097c7f454e693bb971334703e287168b
  Author: Tony Trinh <tony19 at gmail.com>
  Date:   2014-03-31 (Mon, 31 Mar 2014)

  Changed paths:
    M CONTRIBUTING.md

  Log Message:
  -----------
  Update CONTRIBUTING.md