downgrade to kirby v3

vendor/guzzlehttp/psr7/src/Rfc7230.php

@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+namespace GuzzleHttp\Psr7;
+
+/**
+ * @internal
+ */
+final class Rfc7230
+{
+    /**
+     * Header related regular expressions (based on amphp/http package)
+     *
+     * Note: header delimiter (\r\n) is modified to \r?\n to accept line feed only delimiters for BC reasons.
+     *
+     * @see https://github.com/amphp/http/blob/v1.0.1/src/Rfc7230.php#L12-L15
+     *
+     * @license https://github.com/amphp/http/blob/v1.0.1/LICENSE
+     */
+    public const HEADER_REGEX = "(^([^()<>@,;:\\\"/[\]?={}\x01-\x20\x7F]++):[ \t]*+((?:[ \t]*+[\x21-\x7E\x80-\xFF]++)*+)[ \t]*+\r?\n)m";
+    public const HEADER_FOLD_REGEX = "(\r?\n[ \t]++)";
+}