Fix incorrect pvc name (#13)

Cronjob using another name for volume: https://github.com/kvaps/kubernetes-in-kubernetes/blob/master/deploy/helm/kubernetes/templates/etcd-backup-cronjob.yaml#L145

Author: xom4ek

deploy/helm/kubernetes/templates/etcd-backup-persistentvolumeclaim.yaml

@@ -4,7 +4,7 @@
 kind: PersistentVolumeClaim
 apiVersion: v1
 metadata:
-  name: etcd-backup
+  name: etcd-backup-{{ $fullName }}-etcd
   labels:
     app: {{ $fullName }}-etcd
     {{- if .Values.persistence.backup.labels }}