add(template): added pr template

Author: andre-filho

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,11 @@
+## Proposed changes
+(description of our changes and why)
+
+## Screen-shot of changes
+(if it applies)
+
+## Link to issue
+(link issues here, specially if there is more than one issue being solved)
+
+## Other comments
+(is there anything else you want to tell us?)