PULL_REQUEST_TEMPLATE.md

What's the purpose of this PR

XXXXX

Which issue(s) this PR fixes:

Fixes #

Brief changelog

XXXXX

Follow this checklist to help us incorporate your contribution quickly and easily:

• Read the Contributing Guide before making this pull request.
• Write a pull request description that is detailed enough to understand what the pull request does, how, and why.
• Write necessary unit tests to verify the code.
• Run mvn clean test to make sure this pull request doesn't break anything.
• Update the CHANGES log.