Default to RabbitMQ 3.13.6 (#1691)

Author: mkuratczyk

Diff for: README.md

@@ -37,7 +37,7 @@ under `site/kubernetes`.
 
 ## Supported Versions
 
-The operator deploys RabbitMQ `3.13.3` by default, and should work with [any supported RabbitMQ version](https://www.rabbitmq.com/release-information) and [Kubernetes version](https://kubernetes.io/releases/).
+The operator deploys RabbitMQ `3.13.6` by default, and should work with [any supported RabbitMQ version](https://www.rabbitmq.com/release-information) and [Kubernetes version](https://kubernetes.io/releases/).
 
 ## Versioning
 

Diff for: main.go

@@ -58,7 +58,7 @@ func init() {
 func main() {
 	var (
 		metricsAddr             string
-		defaultRabbitmqImage    = "rabbitmq:3.13.3-management"
+		defaultRabbitmqImage    = "rabbitmq:3.13.6-management"
 		controlRabbitmqImage    = false
 		defaultUserUpdaterImage = "rabbitmqoperator/default-user-credential-updater:1.0.2"
 		defaultImagePullSecrets = ""