Add github pull request template

.github/pull_request_template.md

@@ -0,0 +1,12 @@
+<!-- First time contributors: Take a moment to review https://setuptools.readthedocs.io/en/latest/developer-guide.html! -->
+<!-- Remove sections if not applicable -->
+
+## Summary of changes
+
+<!-- Summary goes here -->
+
+Closes <!-- issue number here -->
+
+### Pull Request Checklist
+- [ ] Changes have tests
+- [ ] News fragment added in changelog.d. See [documentation](http://setuptools.readthedocs.io/en/latest/developer-guide.html#making-a-pull-request) for details