Fix: max body size option should actually be passed to HttpServer

Error: Max body size option was not honored
Caused by: $options->withMaxBodySize() returns a new instance containing that option, but that instance was not used

src/Service/HttpProducersServer.php

@@ -69,7 +69,7 @@ public function start(): Promise
             $options = null;
             if ($this->maxBodySize !== null) {
                 $options = new Options();
-                $options->withBodySizeLimit($this->maxBodySize);
+                $options = $options->withBodySizeLimit($this->maxBodySize);
             }
 
             $this->httpServer = new HttpServer(