[bitnami/rabbitmq] Add upgrade note for rabbitmq 3.9 (#7161)

* Add upgrade note for rabbirmq 3.9

* Use right version

* Update bitnami/rabbitmq/README.md

Co-authored-by: Juan Ariza Toledano <juanariza@vmware.com>

* Update Chart.yaml

* Update README.md

* [bitnami/rabbitmq] Update components versions

Signed-off-by: Bitnami Containers <containers@bitnami.com>

Co-authored-by: Carlos Rodríguez Hernández <carlosrh@vmware.com>
Co-authored-by: Juan Ariza Toledano <juanariza@vmware.com>
Co-authored-by: Bitnami Containers <containers@bitnami.com>

bitnami/rabbitmq/Chart.yaml

@@ -1,7 +1,7 @@
 annotations:
   category: Infrastructure
 apiVersion: v2
-appVersion: 3.8.22
+appVersion: 3.9.5
 dependencies:
   - name: common
     repository: https://charts.bitnami.com/bitnami
@@ -23,4 +23,4 @@ name: rabbitmq
 sources:
   - https://github.com/bitnami/bitnami-docker-rabbitmq
   - https://www.rabbitmq.com
-version: 8.20.5
+version: 8.21.0

bitnami/rabbitmq/README.md

@@ -500,6 +500,12 @@ $ helm upgrade my-release bitnami/rabbitmq --set auth.password=[PASSWORD] --set
 
 | Note: you need to substitute the placeholders [PASSWORD] and [RABBITMQ_ERLANG_COOKIE] with the values obtained in the installation notes.
 
+### To 8.21.0
+
+This new version of the chart bumps the RabbitMQ version to `3.9.1`. It is considered a minor release, and no breaking changes are expected. Additionally, RabbitMQ `3.9.X` nodes can run alongside `3.8.X` nodes.
+
+See the [Upgrading guide](https://www.rabbitmq.com/upgrade.html) and the [RabbitMQ change log](https://www.rabbitmq.com/changelog.html) for further documentation.
+
 ### To 8.0.0
 
 [On November 13, 2020, Helm v2 support was formally finished](https://github.com/helm/charts#status-of-the-project), this major version is the result of the required changes applied to the Helm Chart to be able to incorporate the different features added in Helm v3 and to be consistent with the Helm project itself regarding the Helm v2 EOL.

bitnami/rabbitmq/values.yaml

@@ -29,7 +29,7 @@ global:
 image:
   registry: docker.io
   repository: bitnami/rabbitmq
-  tag: 3.8.22-debian-10-r0
+  tag: 3.9.5-debian-10-r0
 
   ## set to true if you would like to see extra information on logs
   ## It turns BASH and/or NAMI debugging in the image
@@ -1118,7 +1118,7 @@ volumePermissions:
   image:
     registry: docker.io
     repository: bitnami/bitnami-shell
-    tag: 10-debian-10-r175
+    tag: 10-debian-10-r180
     ## Specify a imagePullPolicy
     ## Defaults to 'Always' if image tag is 'latest', else set to 'IfNotPresent'
     ## ref: http://kubernetes.io/docs/user-guide/images/#pre-pulling-images