Update Twig from 1.35.0 to 1.42.4 (PHP 5.5 is now required!)

This fixes some errors on PHP 7.4 and contains even more fixes
Also bumped PHP version to 5.5 as Twig requires it.

system/libs/Twig/Extension/DebugExtension.php

@@ -0,0 +1,76 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Twig\Extension {
+use Twig\TwigFunction;
+
+/**
+ * @final
+ */
+class DebugExtension extends AbstractExtension
+{
+    public function getFunctions()
+    {
+        // dump is safe if var_dump is overridden by xdebug
+        $isDumpOutputHtmlSafe = \extension_loaded('xdebug')
+            // false means that it was not set (and the default is on) or it explicitly enabled
+            && (false === ini_get('xdebug.overload_var_dump') || ini_get('xdebug.overload_var_dump'))
+            // false means that it was not set (and the default is on) or it explicitly enabled
+            // xdebug.overload_var_dump produces HTML only when html_errors is also enabled
+            && (false === ini_get('html_errors') || ini_get('html_errors'))
+            || 'cli' === \PHP_SAPI
+        ;
+
+        return [
+            new TwigFunction('dump', 'twig_var_dump', ['is_safe' => $isDumpOutputHtmlSafe ? ['html'] : [], 'needs_context' => true, 'needs_environment' => true, 'is_variadic' => true]),
+        ];
+    }
+
+    public function getName()
+    {
+        return 'debug';
+    }
+}
+
+class_alias('Twig\Extension\DebugExtension', 'Twig_Extension_Debug');
+}
+
+namespace {
+use Twig\Environment;
+use Twig\Template;
+use Twig\TemplateWrapper;
+
+function twig_var_dump(Environment $env, $context, array $vars = [])
+{
+    if (!$env->isDebug()) {
+        return;
+    }
+
+    ob_start();
+
+    if (!$vars) {
+        $vars = [];
+        foreach ($context as $key => $value) {
+            if (!$value instanceof Template && !$value instanceof TemplateWrapper) {
+                $vars[$key] = $value;
+            }
+        }
+
+        var_dump($vars);
+    } else {
+        foreach ($vars as $var) {
+            var_dump($var);
+        }
+    }
+
+    return ob_get_clean();
+}
+}