Member update endpoint can now change ownership

app/Exceptions/Api/ChangingRoleToPlaceholderIsNotAllowed.php

@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Exceptions\Api;
+
+class ChangingRoleToPlaceholderIsNotAllowed extends ApiException
+{
+    public const string KEY = 'changing_role_to_placeholder_is_not_allowed';
+}