[MINOR] Update PR template with documentation update (#6748)

.github/PULL_REQUEST_TEMPLATE.md

@@ -10,6 +10,15 @@ _Describe any public API or user-facing feature change or any performance impact
 
 _Choose one. If medium or high, explain what verification was done to mitigate the risks._
 
+### Documentation Update
+
+_Describe any necessary documentation update if there is any new feature, config, or user-facing change_
+
+- _The config description must be updated if new configs are added or the default value of the configs are changed_
+- _Any new feature or user-facing change requires updating the Hudi website. Please create a Jira ticket, attach the
+  ticket number here and follow the [instruction](https://hudi.apache.org/contribute/developer-setup#website) to make
+  changes to the website._
+
 ### Contributor's checklist
 
 - [ ] Read through [contributor's guide](https://hudi.apache.org/contribute/how-to-contribute)