helm: add namespace to StatefulSet (#14509)

Even if we specify the target namespace by `helm install --namespace`, 
the StatefulSet is created on the default namespace. Since this resource
references the ServiceAccount created on the target namespace, pods are
hindered to be created. To avoid this, we deploy the StatefulSet to the
target namespace of helm.

helm/minio/templates/statefulset.yaml

@@ -38,6 +38,7 @@ apiVersion: {{ template "minio.statefulset.apiVersion" . }}
 kind: StatefulSet
 metadata:
   name: {{ template "minio.fullname" . }}
+  namespace: {{ .Release.Namespace | quote }}
   labels:
     app: {{ template "minio.name" . }}
     chart: {{ template "minio.chart" . }}