Update composer dependencies

vendor/symfony/mime/Encoder/EightBitContentEncoder.php

@@ -0,0 +1,37 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Mime\Encoder;
+
+/**
+ * @author Fabien Potencier <fabien@symfony.com>
+ *
+ * @experimental in 4.3
+ */
+final class EightBitContentEncoder implements ContentEncoderInterface
+{
+    public function encodeByteStream($stream, int $maxLineLength = 0): iterable
+    {
+        while (!feof($stream)) {
+            yield fread($stream, 16372);
+        }
+    }
+
+    public function getName(): string
+    {
+        return '8bit';
+    }
+
+    public function encodeString(string $string, ?string $charset = 'utf-8', int $firstLineOffset = 0, int $maxLineLength = 0): string
+    {
+        return $string;
+    }
+}