Fix tests

Author: TiMESPLiNTER

pkg/enqueue/Symfony/Client/ProduceCommand.php

@@ -57,7 +57,7 @@ protected function execute(InputInterface $input, OutputInterface $output): ?int
         $topic = $input->getOption('topic');
         $command = $input->getOption('command');
         $message = $input->getArgument('message');
-        $headers = $input->getOption('header');
+        $headers = (array) $input->getOption('header');
         $client = $input->getOption('client');
 
         if ($topic && $command) {