Adding PR template

Author: stigi

.github/pull_request_template.md

@@ -0,0 +1,13 @@
+## Change description
+
+<!-- Describe the most significant changes. Focus on the _why_, more than the _what_. -->
+
+## Test Plan
+
+<!-- How did you test the changes, what are the suggested steps for reviewers if they want to test your changes? -->
+
+## Type of Change
+
+- [ ] Bug fix      <!-- fixes an issue -->
+- [ ] Feature      <!-- adds functionality -->
+- [ ] Enhancement  <!-- improves something existing -->