Add doc for OCI installation (#1197)

Author: jonesbusy

charts/jenkins/CHANGELOG.md

@@ -12,6 +12,10 @@ Use the following links to reference issues, PRs, and commits prior to v2.6.0.
 The changelog until v1.5.7 was auto-generated based on git commits.
 Those entries include a reference to the git commit to be able to get more details.
 
+## 5.6.1
+
+Documentation about OCI installation
+
 ## 5.6.0
 
 Helm chart is also now deployed on GitHub packages and can be installed from `oci://ghcr.io/jenkinsci/helm-charts/jenkins`

charts/jenkins/Chart.yaml

@@ -2,7 +2,7 @@ apiVersion: v2
 name: jenkins
 type: application
 home: https://www.jenkins.io/
-version: 5.6.0
+version: 5.6.1
 appVersion: 2.462.2
 description: >
   Jenkins - Build great things at any scale! As the leading open source automation server, Jenkins provides over 1800 plugins to support building, deploying and automating any project.

charts/jenkins/README.md

@@ -23,8 +23,13 @@ _See [`helm repo`](https://helm.sh/docs/helm/helm_repo/) for command documentati
 ## Install Chart
 
 ```console
-# Helm 3
-$ helm install [RELEASE_NAME] jenkins/jenkins [flags]
+helm install [RELEASE_NAME] jenkins/jenkins [flags]
+```
+
+Since version `5.6.0` the chart is available as an OCI image and can be installed using:
+
+```console
+helm install [RELEASE_NAME] oci://ghcr.io/jenkinsci/helm-charts/jenkins [flags]
 ```
 
 _See [configuration](#configuration) below._