Install psalm as dev, sync scripts updates

vendor/amphp/amp/lib/TimeoutException.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace Amp;
+
+/**
+ * Thrown if a promise doesn't resolve within a specified timeout.
+ *
+ * @see \Amp\Promise\timeout()
+ */
+class TimeoutException extends \Exception
+{
+    /**
+     * @param string $message Exception message.
+     */
+    public function __construct(string $message = "Operation timed out")
+    {
+        parent::__construct($message);
+    }
+}