Update 3.13.3 release notes

(cherry picked from commit c4acbf1)

Author: michaelklishin

release-notes/3.13.3.md

@@ -140,6 +140,12 @@ Release notes can be found on GitHub at [rabbitmq-server/release-notes](https://
 
 #### Bug Fixes
 
+ * `rabbitmqctl delete_shovel` is now more effective at deleting Shovels that
+    cannot start (for example, because they cannot connect using the configured URIs) and
+    repeatedly fail, get restarted, fail again, get restarted, and so on.
+
+    GitHub issue: [#11324](https://github.com/rabbitmq/rabbitmq-server/pull/11324)
+
  * `fail_if_no_peer_cert`, a server-side TLS setting, was removed from Shovel URI examples.
     Erlang 26's TLS implementation will refuse to accept it as a client-side setting whereas
     previously it was quietly ignored.