chore: add pr template (#128)

Author: sysvm

.github/pull_request_template.md

@@ -0,0 +1,21 @@
+### Description
+
+add a description of your changes here...
+
+### Rationale
+
+tell us why we need these changes...
+
+### Example
+
+add an example CLI or API response...
+
+### Changes
+
+Notable changes: 
+* add each change in a bullet point here
+* ...
+
+### Potential Impacts
+* add potential impacts for other components here
+* ...