[dist] Add PR template. (godaddy#2)

Author: indexzero

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,23 @@
+<!--
+Thanks for submitting a pull request! We appreciate you spending the time to work on these changes.
+Please provide enough information so that others can review your pull request. The three fields below are mandatory.
+-->
+
+## Summary
+
+<!--
+Explain the **motivation** for making this change. What existing problem does the pull request solve?
+-->
+
+## Changelog
+
+<!--
+Help reviewers and the release process by writing your own changelog entry. See this project's CHANGELOG.md
+for an example.
+-->
+
+## Test Plan
+
+<!--
+Demonstrate the code is solid. Example: The exact commands you ran and their output, screenshots / videos if the pull request changes UI.
+-->