[es] Avoid YAML parsing error in kustomization.yaml

Author: Arhell

content/es/docs/tasks/manage-kubernetes-objects/kustomization.md

@@ -710,7 +710,7 @@ resources:
 images:
 - name: nginx
  newName: my.image.registry/nginx
- newTag: 1.4.0
+ newTag: "1.4.0"
 EOF
 ```
 Ejecuta `kubectl kustomize ./` para ver que el campo `image` ha sido actualizado: