chore: Add pull request template to repository (#208)

Author: tmathern

.github/PULL_REQUEST_TEMPLATE

@@ -0,0 +1,7 @@
+## Changes in this pull request
+_Give a narrative description of what has been changed._
+
+## Checklist
+- [ ] This PR represents a single feature, fix, or change.
+- [ ] All applicable changes have been documented.
+- [ ] Any `TO DO` items (or similar) have been entered as GitHub issues and the link to that issue has been included in a comment.