PR template (#5093)

Add Github PR template

.github/pull_request_template.md

@@ -0,0 +1,33 @@
+## Description
+
+<!-- For small changes (<=3 files and <=50 lines of codes in the source folder), -->
+<!-- you may remove Sections 1-3 below and just provide a simple description here -->
+
+### 1. Why the change?
+
+<!-- Provide the related github issue link if available -->
+
+### 2. Summary of the change
+
+<!-- Provide the design for both API changes and the implementation; -->
+<!-- alternatively, provide a link to the github issue link for the design -->
+
+### 3. How to test?
+- [ ] N/A
+- [ ] Unit test
+- [ ] Application test
+- [ ] Document test
+- [ ] ...
+
+### 4. New dependencies
+
+<!-- If no new dependency is introduced, remove this section -->
+
+- [ ] New Python dependencies
+       - Dependency1 
+       - Dependency2
+       - ...
+- [ ] New Java/Scala dependencies and their license
+       - Dependency1 and license1
+       - Dependency2 and license2
+       - ...