Update PR template

.github/PULL_REQUEST_TEMPLATE.md

@@ -2,18 +2,21 @@
 1. If this is your first time, read our contributor guidelines https://git.k8s.io/community/contributors/devel/pull-requests.md#the-pr-submit-process and developer guide https://git.k8s.io/community/contributors/devel/development.md#development-guide
 2. If you want *faster* PR reviews, read how: https://git.k8s.io/community/contributors/devel/pull-requests.md#best-practices-for-faster-reviews
 3. Follow the instructions for writing a release note: https://git.k8s.io/community/contributors/devel/pull-requests.md#write-release-notes-if-needed
+4. If the PR is unfinished, see how to mark it: https://github.com/kubernetes/community/blob/master/contributors/devel/pull-requests.md#marking-unfinished-pull-requests
 -->
 
 **What this PR does / why we need it**:
 
-**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #
+**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
+Fixes #
 
 **Special notes for your reviewer**:
 
 **Release note**:
-<!--  Steps to write your release note:
-1. Use the release-note-* labels to set the release note state (if you have access)
-2. Enter your extended release note in the below block; leaving it blank means using the PR title as the release note. If no release note is required, just write `NONE`.
+<!--  Write your release note:
+1. Enter your extended release note in the below block. If the PR requires additional action from users switching to the new release, include the string "action required".
+2. If no release note is required, just write "NONE".
 -->
 ```release-note
+
 ```