Fix the config name in the basic example

Change-Id: If5bbedcc4aa9d730cc8d18be8e7b8d6980303ade

Author: tejal29

mmv1/templates/terraform/examples/workstation_config_basic.tf.tmpl

@@ -58,8 +58,8 @@ resource "google_workstations_workstation_config" "{{$.PrimaryResourceId}}" {
     "label" = "key"
   }
 
-  maxUsableWorkstations = 1
-
+  max_usable_workstations = 1 
+  
   host {
     gce_instance {
       machine_type                = "e2-standard-4"