fix prior blog post url

Author: alexzielenski

content/en/blog/_posts/2022-09-29-immutability-with-cel.md

@@ -653,4 +653,4 @@ For native types, the same behavior can be achieved using kube-openapi’s marke
 Usage of CEL within Kubernetes Validation Rules is so much more powerful than
 what has been shown in this article. For more information please check out
 [validation rules](https://kubernetes.io/docs/tasks/extend-kubernetes/custom-resources/custom-resource-definitions/#validation-rules)
-in the Kubernetes documentation and [CRD Validation Rules Beta](https://kubernetes.io/blog/2022-09-23/crd-validation-rules-beta) blog post.
+in the Kubernetes documentation and [CRD Validation Rules Beta](https://kubernetes.io/blog/2022/09/23/crd-validation-rules-beta/) blog post.