Add PR template (#59)

Author: bryan-aguilar

.github/pull_request_template.md

@@ -0,0 +1,13 @@
+**Description:** <Describe what has changed.>
+<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
+Ex. Adding a feature - Explain what this achieves.-->
+
+**Link to tracking Issue:** <Issue number if applicable>
+
+**Testing:** <Describe what testing was performed and which tests were added.>
+
+**Documentation:** <Describe the documentation added.>
+
+
+<!-- DO NOT DELETE -->
+By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.