add pr template (#827)

Co-authored-by: heya02 <heya02@baidu.com>

Author: hysunflower

.github/PULL_REQUEST_TEMPLATE.md

@@ -0,0 +1,8 @@
+### PR types
+<!-- One of [ New features | Bug fixes | Function optimization | Performance optimization | Breaking changes | Others ] -->
+
+### PR changes
+<!-- One of [ OPs | APIs | Docs | Others ] -->
+
+### Describe
+<!-- Describe what this PR does -->