Add doc requirements to PR template (magento#739)

Author: meker12

.github/PULL_REQUEST_TEMPLATE.md

@@ -12,6 +12,8 @@
 <!---
     Please provide a description of the changes proposed in the pull request.
     Letting us know what has changed and why it needed changing will help us validate this pull request.
+
+    If this PR was initiated by an internal JIRA ticket, copy the description from the ticket here so that the information is visible to contributors from the Magento Cloud Community.
 -->
 
 ### Fixed Issues (if relevant)
@@ -30,8 +32,19 @@
 1. ...
 2. ...
 
+### Release notes
+
+For user-facing changes, add a meaningful release note. For examples, see [Magento Cloud ECE-tools release notes](https://devdocs.magento.com/cloud/release-notes/ece-release-notes.html).
+
+### Associated documentation updates
+<!--
+ If your proposed update requires user documentation, submit a PR to the Magento DevDocs repository. For extensive updates requiring assistance, submit an issue to DevDocs. See https://github.com/magento/devdocs/blob/master/.github/CONTRIBUTING.md.
+ -->
+Add link to Magento DevDocs PR or Issue, if needed.
+
 ### Contribution checklist
  - [ ] Pull request has a meaningful description of its purpose
+ - [ ] Pull request introduces user-facing changes and includes meaningful updates for any required release notes and documentation changes
  - [ ] All commits are accompanied by meaningful commit messages
  - [ ] All new or changed code is covered with unit/integration tests (if applicable)
  - [ ] All automated tests passed successfully (all builds on Travis CI are green)