fix: remove unused volume

cluster/apps/data/bookstack/kustomization.yaml

@@ -3,4 +3,4 @@ kind: Kustomization
 resources:
   - export-job.yaml
   - helm-release.yaml
-  - volumes.yaml
+  - volume.yaml

cluster/apps/data/bookstack/volume.yaml

@@ -13,18 +13,3 @@ spec:
   resources:
     requests:
       storage: 5Gi
----
-apiVersion: v1
-kind: PersistentVolumeClaim
-metadata:
-  name: bookstack-db
-  namespace: data
-  labels:
-    kasten-io/backup: "true"
-spec:
-  accessModes:
-    - ReadWriteOnce
-  storageClassName: rook-ceph-block
-  resources:
-    requests:
-      storage: 5Gi