downgrade to kirby v3

vendor/ml/json-ld/QuadSerializerInterface.php

@@ -0,0 +1,27 @@
+<?php
+
+/*
+ * (c) Markus Lanthaler <mail@markus-lanthaler.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace ML\JsonLD;
+
+/**
+ * Quad serializer interface
+ *
+ * @author Markus Lanthaler <mail@markus-lanthaler.com>
+ */
+interface QuadSerializerInterface
+{
+    /**
+     * Serializes quads to a string.
+     *
+     * @param Quad[] $quads Array of quads to be serialized.
+     *
+     * @return string The serialized quads.
+     */
+    public function serialize(array $quads);
+}