Adjust newFactory method visibility (#1735)

This method overrides the newFactory() method in the HasFactory trait, which is protected, resulting in a fatal error in PHP 8.3

src/Client.php

@@ -233,7 +233,7 @@ public function getIncrementing()
      *
      * @return \Illuminate\Database\Eloquent\Factories\Factory
      */
-    public static function newFactory()
+    protected static function newFactory()
     {
         return ClientFactory::new();
     }