Add the backup command and fix the sync issue maybe

Signed-off-by: Martyn Ranyard <m@rtyn.berlin>

kustomized-helms/pg4nc/statefulset.yaml

@@ -3,6 +3,8 @@ kind: StatefulSet
 metadata:
   name: pg4nc-postgres
   namespace: nextcloud
+  annotations:
+    k8up.io/backupcommand: /usr/bin/pg_dumpall -U nextcloud
 spec:
   template:
     spec:
@@ -12,7 +14,7 @@ spec:
         - name: PGDATA
           $patch: delete
         securityContext:
-          fsGroup: 0
+          $patch: delete 
 ---
 apiVersion: apps/v1
 kind: StatefulSet