Add #10275 #12765 to 4.1.0 release notes

Author: michaelklishin

release-notes/4.0.1.md

@@ -356,6 +356,12 @@ This section is incomplete and will be expanded as 4.0 approaches its release ca
 
    GitHub issue: [#11743](https://github.com/rabbitmq/rabbitmq-server/issues/11743)
 
+ * Several new metrics for streams, for example, `stream_consumer_max_offset_lag`.
+
+   Contributed by @markus812498, @gomoripeti.
+
+   GitHub issue: [#10275](https://github.com/rabbitmq/rabbitmq-server/pull/10275)
+
  * New per-exchange and per-queue metrics.
 
    Contributed by @LoisSotoLopez.