feat: update stability of Certificate Manager

Signed-off-by: Giovanni Liva <[email protected]>

README.md

@@ -19,7 +19,7 @@ Status of the different features:
   K8s Custom Metrics: expose your Observability platform via the [Custom Metric API](https://github.com/kubernetes/design-proposals-archive/blob/main/instrumentation/custom-metrics-api.md).
 - ![status](https://img.shields.io/badge/status-alpha-orange)
   Release lifecycle: handle pre- and post-checks of your Application deployment.
-- ![status](https://img.shields.io/badge/status-beta-yellow)
+- ![status](https://img.shields.io/badge/status-stable-brightgreen)
   Certificate Manager: automatically configure TLS certificates for
   [secure communication with the Kube API](https://kubernetes.io/docs/concepts/security/controlling-access/#transport-security).
 
@@ -29,6 +29,8 @@ beta ![status](https://img.shields.io/badge/status-beta-yellow) )
 stable ![status](https://img.shields.io/badge/status-stable-brightgreen) )
 -->
 
+The status follows the [Kubernetes API versioning schema](https://kubernetes.io/docs/reference/using-api/#api-versioning).
+
 For more info about the features, please refer to our [documentation](https://lifecycle.keptn.sh/docs/).
 
 ## Watch the KubeCon 2022 Detroit Demo