fix PR-template

Author: Chao Wang

.github/PULL_REQUEST_TEMPLATE.md

@@ -38,7 +38,6 @@ Fixes #
 If no, just write "NONE".
 If yes, a release note is required:
 Enter your extended release note in the block below. If the PR requires additional action from users switching to the new release, include the string "action required".
-2. 
 -->
 ```release-note