add a pull request template (#790)

Co-authored-by: Asif Saif Uddin <[email protected]>

Author: n2ygk

.github/pull_request_template.md

@@ -0,0 +1,12 @@
+Fixes #
+
+## Description of the Change
+
+## Checklist
+
+- [ ] PR only contains one change (considered splitting up PR)
+- [ ] unit-test added
+- [ ] documentation updated
+- [ ] `CHANGELOG.md` updated (only for user relevant changes)
+- [ ] `docs/changelog.rst` updated to match.
+- [ ] author name in `AUTHORS`