Update kubeconfig.template

modules/garr_horizon_dashboard_customization_module/templates/kubeconfig.template

@@ -19,7 +19,7 @@ users:
         apiVersion: client.authentication.k8s.io/v1beta1
         command: bin/kubectl-keystone-auth
         args:
-        - "--keystone-url=keystone-prod.cloud.garr.it:4990"
+        - "--keystone-url=https://keystone-prod.cloud.garr.it:4990/v3"
         - "--domain-name=none"
         - "--user-name={{ user.username }}"
         - "--application-credential-name={{ application_credential_name }}"