Add note on production promotions

Signed-off-by: Stefan Prodan <stefan.prodan@gmail.com>

README.md

@@ -145,6 +145,9 @@ kind: HelmRelease
 metadata:
   name: ingress-nginx
 spec:
+  chart:
+    spec:
+      version: ">=4.10.0"
   values:
     controller:
       replicaCount: 2
@@ -187,6 +190,12 @@ NAME                       READY   UP-TO-DATE
 ingress-nginx-controller   2/2     2
 ```
 
+> [!IMPORTANT]
+> Note that on production clusters, it is recommended to pin the Helm chart to an exact
+> version and to use a promotion workflow to test new versions on the staging cluster before
+> deploying to production. For more information, see the guide
+> [Promote Flux Helm Releases with GitHub Actions](https://fluxcd.io/flux/use-cases/gh-actions-helm-promotion/).
+
 ## Testing
 
 After making changes to the manifests, you can validate them locally with [kubeconform](https://github.com/yannh/kubeconform) by running:

clusters/production/infra-controllers/ingress-nginx-values.yaml

@@ -1,8 +0,0 @@
-apiVersion: helm.toolkit.fluxcd.io/v2beta2
-kind: HelmRelease
-metadata:
-  name: ingress-nginx
-spec:
-  values:
-    controller:
-      replicaCount: 2

clusters/production/infra-controllers/kustomization.yaml

@@ -2,8 +2,3 @@ apiVersion: kustomize.config.k8s.io/v1beta1
 kind: Kustomization
 resources:
   - ../../../deploy/infra-controllers
-patches:
-  - target:
-      kind: HelmRelease
-      name: ingress-nginx
-    path: ingress-nginx-values.yaml