fix: 适配php7.4以下的语法

template/Endpoint.temp

@@ -45,14 +45,14 @@ class {{ Endpoint }}
 *
      * @param Closure|null $catch
      * @param Closure|null $then
-     * @return array
+     * @return mixed
      *
      * @throws ApplicationException
      * @throws SdkException
      * @throws TimeOutExcetpion
      * @throws GuzzleException
      */
-    public function {{ item.Action }}({{ item.Args }}?Closure $catch = null, ?Closure $then = null): mixed
+    public function {{ item.Action }}({{ item.Args }}?Closure $catch = null, ?Closure $then = null)
     {
         $url = "{{ item.Uri }}";
 {% if item.Join|length > 0 %}