Allow postService() method to set description property

You cannot set `description` for a new service right now, I see the patchService() method have it, so I added it also for the creation.

Author: samuel4x4

src/Identity/v3/Api.php

@@ -61,6 +61,7 @@ public function postServices(): array
             'params'  => [
                 'name' => $this->params->name('service'),
                 'type' => $this->params->type('service'),
+                'description' => $this->params->desc('service'),
             ]
         ];
     }