Removed the need for Kustomize in prerequisites (bregman-arie#332)

Since 1.14, Kubectl also supports the management of Kubernetes objects using a kustomization file.
cf. https://kubernetes.io/docs/tasks/manage-kubernetes-objects/kustomization/#bases-and-overlays

Author: chimons

topics/kubernetes/exercises/kustomize_common_labels/exercise.md

@@ -3,7 +3,7 @@
 ## Requirements
 
 1. Running Kubernetes cluster
-2. Kustomize binary installed
+2. Kubctl version 1.14 or above
 
 ## Objectives
 
@@ -14,4 +14,4 @@ In the current directory there is an app composed of a Deployment and Service.
 
 ## Solution
 
-Click [here](solution.md) to view the solution
+Click [here](solution.md) to view the solution