Install psalm as dev, sync scripts updates

vendor/felixfbecker/language-server-protocol/src/CodeActionDisabled.php

@@ -0,0 +1,21 @@
+<?php
+
+namespace LanguageServerProtocol;
+
+class CodeActionDisabled
+{
+    /**
+     * Human readable description of why the code action is currently
+     * disabled.
+     *
+     * This is displayed in the code actions UI.
+     *
+     * @var string
+     */
+    public $reason;
+
+    public function __construct(string $reason)
+    {
+        $this->reason = $reason;
+    }
+}