[zanata/zanata-platform] 172cca: doc: Update PR template

[GitHub]

  Branch: refs/heads/ZNTA-1952-Pr-template
  Home:   https://github.com/zanata/zanata-platform
  Commit: 172cca3377cbddb9c0b62d7a2c13d0e6ee840a6a
      https://github.com/zanata/zanata-platform/commit/172cca3377cbddb9c0b62d7a2c13d0e6ee840a6a
  Author: Alex Eng <aeng at redhat.com>
  Date:   2017-10-05 (Thu, 05 Oct 2017)

  Changed paths:
    M .github/PULL_REQUEST_TEMPLATE.md
    M CONTRIBUTING.md

  Log Message:
  -----------
  doc: Update PR template

https://zanata.atlassian.net/browse/ZNTA-1952