Docs: Another minor edit

WORKFLOW.md

@@ -65,6 +65,8 @@ PRs intended for inclusion in the next PATCH release they must be backported to
 
 
 [Read more on backport PRs](https://github.com/grafana/grafana/blob/master/.github/bot.md)
 [Read more on backport PRs](https://github.com/grafana/grafana/blob/master/.github/bot.md)
 
 
+* Both the source PR and the backport PR should be assigned to the patch release milestone, unless you are backporting to many releases then it can differ. 
+
 Releases follow the following cadence
 Releases follow the following cadence
 - MAJOR: Yearly
 - MAJOR: Yearly
 - MINOR: Every 4-6 weeks
 - MINOR: Every 4-6 weeks