use existing secret for wmill pg

apps/base/piko/kustomization.yaml

@@ -0,0 +1,7 @@
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+namespace: futureporn
+resources:
+  - namespace.yaml
+  - repository.yaml
+  - release.yaml

apps/base/piko/namespace.yaml

@@ -0,0 +1,4 @@
+apiVersion: v1
+kind: Namespace
+metadata:
+  name: piko

apps/base/windmill/windmill.yaml

@@ -27,8 +27,8 @@ spec:
     fullnameOverride: windmill-postgresql
     postgresql:
       auth:
-        postgresPassword: blahblahblah
         database: windmill
+        existingSecret: windmill-postgres
     primary:
       persistence:
         # It would be $0.20/mo cheaper to use 8Gi NVMe,