add ztwim stable channel overlay

Author: euanhume

zero-trust-workload-identity-manager/operator/overlays/stable-v1/kustomization.yaml

@@ -0,0 +1,14 @@
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+resources:
+  - ../../base
+
+patches:
+  - target:
+      kind: Subscription
+      name: openshift-zero-trust-workload-identity-manager
+    patch: |-
+      - op: replace
+        path: /spec/channel
+        value: 'stable-v1'