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/TokenParser/SandboxTokenParser.php

@@ -0,0 +1,67 @@
+<?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\TokenParser;
+
+use Twig\Error\SyntaxError;
+use Twig\Node\IncludeNode;
+use Twig\Node\SandboxNode;
+use Twig\Node\TextNode;
+use Twig\Token;
+
+/**
+ * Marks a section of a template as untrusted code that must be evaluated in the sandbox mode.
+ *
+ *    {% sandbox %}
+ *        {% include 'user.html' %}
+ *    {% endsandbox %}
+ *
+ * @see https://twig.symfony.com/doc/api.html#sandbox-extension for details
+ *
+ * @final
+ */
+class SandboxTokenParser extends AbstractTokenParser
+{
+    public function parse(Token $token)
+    {
+        $stream = $this->parser->getStream();
+        $stream->expect(Token::BLOCK_END_TYPE);
+        $body = $this->parser->subparse([$this, 'decideBlockEnd'], true);
+        $stream->expect(Token::BLOCK_END_TYPE);
+
+        // in a sandbox tag, only include tags are allowed
+        if (!$body instanceof IncludeNode) {
+            foreach ($body as $node) {
+                if ($node instanceof TextNode && ctype_space($node->getAttribute('data'))) {
+                    continue;
+                }
+
+                if (!$node instanceof IncludeNode) {
+                    throw new SyntaxError('Only "include" tags are allowed within a "sandbox" section.', $node->getTemplateLine(), $stream->getSourceContext());
+                }
+            }
+        }
+
+        return new SandboxNode($body, $token->getLine(), $this->getTag());
+    }
+
+    public function decideBlockEnd(Token $token)
+    {
+        return $token->test('endsandbox');
+    }
+
+    public function getTag()
+    {
+        return 'sandbox';
+    }
+}
+
+class_alias('Twig\TokenParser\SandboxTokenParser', 'Twig_TokenParser_Sandbox');