feat: prevent running duplicate restic jobs

restic/Chart.yaml

@@ -2,5 +2,5 @@ apiVersion: v2
 name: restic
 description: Helm Chart for restic
 type: application
-version: 1.2.0
+version: 1.3.0
 appVersion: "0.13.1"

restic/templates/cronjob.yaml

@@ -5,6 +5,7 @@ metadata:
   labels:
     {{- include "restic-helm.labels" . | nindent 4 }}
 spec:
+  concurrencyPolicy: Forbid
   schedule: "{{ .Values.schedule }}"
   jobTemplate:
     metadata: