[stable/magento] Fix chart not being upgradable (#7813)

* [stable/magento] Fix chart not being upgradable

Signed-off-by: Javier J. Salmeron Garcia <jsalmeron@bitnami.com>

* Change readme

Signed-off-by: Javier J. Salmeron Garcia <jsalmeron@bitnami.com>

stable/magento/Chart.yaml

@@ -1,5 +1,5 @@
 name: magento
-version: 2.0.6
+version: 3.0.0
 appVersion: 2.2.6
 description: A feature-rich flexible e-commerce solution. It includes transaction options, multi-store functionality, loyalty programs, product categorization and shopper filtering, promotion rules, and more.
 keywords:

stable/magento/README.md

@@ -122,3 +122,14 @@ The [Bitnami Magento](https://github.com/bitnami/bitnami-docker-magento) image s
 
 Persistent Volume Claims are used to keep the data across deployments. This is known to work in GCE, AWS, and minikube.
 See the [Configuration](#configuration) section to configure the PVC or to disable persistence.
+
+## Upgrading
+
+### To 3.0.0
+
+Backwards compatibility is not guaranteed unless you modify the labels used on the chart's deployments.
+Use the workaround below to upgrade from versions previous to 3.0.0. The following example assumes that the release name is magento:
+
+```console
+$ kubectl patch deployment magento-magento --type=json -p='[{"op": "remove", "path": "/spec/selector/matchLabels/chart"}]'
+$ kubectl delete statefulset magento-mariadb --cascade=false

stable/magento/templates/deployment.yaml

@@ -9,6 +9,10 @@ metadata:
     release: "{{ .Release.Name }}"
     heritage: "{{ .Release.Service }}"
 spec:
+  selector:
+    matchLabels:
+      app: {{ template "magento.fullname" . }}
+      release: "{{ .Release.Name }}"
   template:
     metadata:
       labels: