Add a pull request template.

Author: thedodd

.github/pull_request_template.md

@@ -0,0 +1,10 @@
+<!--
+Thank you for taking the time to open a pull request!
+Please review the checklist below and perform each of
+the applicable tasks. ❤️!
+-->
+**Checklist**
+- [ ] Updated CHANGELOG.md describing pertinent changes.
+- [ ] Updated README.md with pertinent info (may not always apply). <!-- Mark complete if nothing to do. -->
+- [ ] Updated guide with pertinent info (may not always apply). <!-- Mark complete if nothing to do. -->
+- [ ] Squash down commits to one or two logical commits which clearly describe the work you've done. If you don't, then Dodd will `:)`.