chore(github): add PR template

.github/pull_request_template.md

@@ -0,0 +1,22 @@
+##### SUMMARY
+<!--- Describe the change below, including rationale and design decisions -->
+
+<!--- HINT: Include "Fixes #nnn" if you are fixing an existing issue -->
+
+##### ISSUE TYPE
+<!--- Pick one or more below and delete the rest.
+      'Test Pull Request' is for PRs that add/extend tests without code changes. -->
+- Bugfix Pull Request
+- Docs Pull Request
+- Feature Pull Request
+- Refactoring Pull Request
+- Test Pull Request
+
+##### ADDITIONAL INFORMATION
+<!--- Include additional information to help people understand the change here -->
+<!--- A step-by-step reproduction of the problem is helpful if there is no related issue -->
+
+<!--- Paste verbatim command output below, e.g. before and after your change -->
+```paste below
+
+```