Merge pull request #4411 from rabbitmq/mk-update-3.10-changelog

Update 3.10.0 release notes

(cherry picked from commit e83b966)

Author: michaelklishin

release-notes/3.10.0.md

@@ -193,6 +193,11 @@ This release includes all bug fixes that shipped in `3.9.x` releases.
 
    GitHub issue: [#4073](https://github.com/rabbitmq/rabbitmq-server/pull/4073)
 
+ * Stream delivery rate could drop if concurrent stream consumers consumed in a way
+   that made them reach the end of the stream often.
+
+   GitHub issue: [#4371](https://github.com/rabbitmq/rabbitmq-server/pull/4371)
+
  * Channels could confirm a subset of messages published as mandatory in some cases.
 
    GitHub issue: [#3870](https://github.com/rabbitmq/rabbitmq-server/pull/3870)
@@ -209,6 +214,22 @@ This release includes all bug fixes that shipped in `3.9.x` releases.
 
    GitHub issue: [#3341](https://github.com/rabbitmq/rabbitmq-server/pull/3341)
 
+### Management Plugin
+
+ * `idle_since` field now uses RFC 3339 format.
+
+   ![Breaking change](https://img.shields.io/badge/-Breaking%20change-red) This is a **potentially breaking change**.
+   Sample value with the previous format: `2022-03-22 11:39:37`. With the new format: `2022-03-22T11:39:37.908+01:00`.
+   Clients of the REST API should be able to parse values in the new format.
+
+   GitHub issue: [#4276](https://github.com/rabbitmq/rabbitmq-server/issues/4276)
+
+ * `rabbitmqadmin` now correctly loads TLS-related keys from its configuration file.
+
+   Contributed by @fwolfsjaeger.
+
+   GitHub issue: [#4408](https://github.com/rabbitmq/rabbitmq-server/pull/4408)
+
 
 ### OAuth 2 AuthN and AuthZ Backend Plugin