Install psalm as dev, sync scripts updates

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

@@ -0,0 +1,33 @@
+<?php
+
+namespace LanguageServerProtocol;
+
+class RegularExpressionsClientCapabilities
+{
+
+    /**
+     * The engine's name.
+     *
+     * @var string
+     */
+    public $engine;
+
+    /**
+     * The engine's version.
+     *
+     * @var string|null
+     */
+    public $version;
+
+
+    /**
+     * @param string $engine
+     * @param string|null $version
+     */
+    public function __construct(string $engine = null, string $version = null)
+    {
+        /** @psalm-suppress PossiblyNullPropertyAssignmentValue */
+        $this->engine = $engine;
+        $this->version = $version;
+    }
+}