Adds a PR template (#255)

* Adds a PR template

Aims to standardize PR submissions for easier review  and ensure
that contributors are being prompted to: update version, add
documentation, add tests, and test locally as applicable.

* Fix template name

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,20 @@
+Include any related JIRA issue keys in the PR title, eg `QPPA-1234 Add measures x, y, and z`.
+
+#### Motivation for change
+
+What is the problem being solved? What is the feature being added?
+
+#### What is being changed
+
+Detailed information about what is being changed and rationale for interesting decisions made
+
+#### Release checklist:
+Tasks that must be done prior to merging this PR, including testing.
+
+* [ ] [Package version updated](../CONTRIBUTING.md#versioning-publishing-and-creating-new-releases)
+* [ ] Documentation updated
+* [ ] Unit tests added/passing
+* [ ] Verified working locally
+
+##### Associated JIRA tickets:
+* https://jira.cms.gov/browse/QPPA-XXXX