Substitute cluster env variable

clusters/testing/flux-system/kustomization.yaml

@@ -1,5 +1,15 @@
 apiVersion: kustomize.config.k8s.io/v1beta1
 kind: Kustomization
 resources:
-- gotk-components.yaml
-- gotk-sync.yaml
+  - gotk-components.yaml
+  - gotk-sync.yaml
+patches:
+  - patch: |
+      - op: add
+        path: /spec/postBuild
+        value:
+          substitute:
+            cluster_env: staging
+    target:
+      kind: Kustomization
+      name: flux-system

clusters/testing/kustomization.yaml

@@ -6,4 +6,4 @@ resources:
   - ../../controllers/cert-manager/cert-manager.yaml
   - ../../configs/artifacts.yaml
   - ../../configs/letsencrypt/letsencrypt.yaml
-  - ../../configs/certificates/staging/certificates.yaml
+  - ../../configs/certificates/certificates.yaml