add namespace to secret

kubernetes/apps/cert-manager/cert-manager.yaml

@@ -1,5 +1,23 @@
 apiVersion: kustomize.toolkit.fluxcd.io/v1
 kind: Kustomization
+metadata:
+  name: cert-manager-secrets
+  namespace: flux-system
+spec:
+  interval: 1h
+  path: ./kubernetes/apps/cert-manager/app
+  prune: true
+  sourceRef:
+    kind: GitRepository
+    namespace: flux-system
+    name: home-cluster-ops
+  decryption:
+    provider: sops
+    secretRef:
+      name: sops-gpg
+---
+apiVersion: kustomize.toolkit.fluxcd.io/v1
+kind: Kustomization
 metadata:
   name: cert-manager
   namespace: cert-manager