chore: change example to use no shell

README.md

@@ -12,7 +12,7 @@ require_once __DIR__ . '/vendor/autoload.php';
 
 $child = (new Command('/usr/bin/cat'))
     ->stdin(Stdio::piped('r'))
-    ->spawn(shell: true);
+    ->spawn(shell: false);
 
 $child->stdin?->write('Hello, this is pretty cool.');
 $child->stdin?->close();