Update 3.10.20 release notes

(cherry picked from commit e860be1)
(cherry picked from commit e2abaf3)
(cherry picked from commit d9ffac7)

Author: michaelklishin

release-notes/3.10.20.md

@@ -30,6 +30,18 @@ Release notes can be found on GitHub at [rabbitmq-server/release-notes](https://
 
 ### Bug Fixes
 
+ * Boot time import of definitions from a `conf.d`-style directory failed unless
+   `definitions.skip_if_unchanged` was set to `true`, for example, like in this
+   `rabbitmq.conf`:
+
+   ``` ini
+   definitions.skip_if_unchanged = false
+   definitions.import_backend = local_filesystem
+   definitions.local.path = /path/to/RabbitMQ/definitions/conf.d/
+   ```
+
+   GitHub issue: [#7705](https://github.com/rabbitmq/rabbitmq-server/pull/7705)
+
  * Improved resiliency of dead-lettering.
 
    GitHib issue: [#7677](https://github.com/rabbitmq/rabbitmq-server/pull/7677)
@@ -46,6 +58,18 @@ Release notes can be found on GitHub at [rabbitmq-server/release-notes](https://
    GitHub issue: [#7657](https://github.com/rabbitmq/rabbitmq-server/pull/7657)
 
 
+## Management Plugin
+
+### Bug Fixes
+
+ * HTTP API will now respond with a `405 Method Not Allowed` instead of a 500 when
+   an unsupported method is used by the client.
+
+   Contributed by @gomoripeti (CloudAMQP).
+
+   GitHub issue: [#7675](https://github.com/rabbitmq/rabbitmq-server/pull/7675)
+
+
 ### etcd Peer Discovery Plugin
 
 #### Bug Fixes