fix: PersistentVolumeClaim are not cleaned up after cluster deletion

Author: teoincontatto

stackgres-k8s/src/operator/src/test/java/io/stackgres/operator/conciliation/factory/cluster/KubernetessMockResourceGenerationUtil.java

@@ -154,6 +154,7 @@ public static List<HasMetadata> buildResources(StackGresCluster cluster) {
         new PodBuilder()
             .withNewMetadata().withName(name + "-0").withNamespace(namespace)
             .withLabels(labelFactory.clusterReplicaLabels(cluster))
+            .withOwnerReferences(List.of(ResourceUtil.getOwnerReference(cluster)))
             .endMetadata()
             .withSpec(new PodSpecBuilder()
                 .addNewContainer()