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/SetTokenParser.php

@@ -0,0 +1,74 @@
+<?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\SetNode;
+use Twig\Token;
+
+/**
+ * Defines a variable.
+ *
+ *  {% set foo = 'foo' %}
+ *  {% set foo = [1, 2] %}
+ *  {% set foo = {'foo': 'bar'} %}
+ *  {% set foo = 'foo' ~ 'bar' %}
+ *  {% set foo, bar = 'foo', 'bar' %}
+ *  {% set foo %}Some content{% endset %}
+ *
+ * @final
+ */
+class SetTokenParser extends AbstractTokenParser
+{
+    public function parse(Token $token)
+    {
+        $lineno = $token->getLine();
+        $stream = $this->parser->getStream();
+        $names = $this->parser->getExpressionParser()->parseAssignmentExpression();
+
+        $capture = false;
+        if ($stream->nextIf(Token::OPERATOR_TYPE, '=')) {
+            $values = $this->parser->getExpressionParser()->parseMultitargetExpression();
+
+            $stream->expect(Token::BLOCK_END_TYPE);
+
+            if (\count($names) !== \count($values)) {
+                throw new SyntaxError('When using set, you must have the same number of variables and assignments.', $stream->getCurrent()->getLine(), $stream->getSourceContext());
+            }
+        } else {
+            $capture = true;
+
+            if (\count($names) > 1) {
+                throw new SyntaxError('When using set with a block, you cannot have a multi-target.', $stream->getCurrent()->getLine(), $stream->getSourceContext());
+            }
+
+            $stream->expect(Token::BLOCK_END_TYPE);
+
+            $values = $this->parser->subparse([$this, 'decideBlockEnd'], true);
+            $stream->expect(Token::BLOCK_END_TYPE);
+        }
+
+        return new SetNode($capture, $names, $values, $lineno, $this->getTag());
+    }
+
+    public function decideBlockEnd(Token $token)
+    {
+        return $token->test('endset');
+    }
+
+    public function getTag()
+    {
+        return 'set';
+    }
+}
+
+class_alias('Twig\TokenParser\SetTokenParser', 'Twig_TokenParser_Set');