Add pjson support

tests/PjsonId.php

@@ -0,0 +1,23 @@
+<?php declare(strict_types=1);
+
+namespace Test;
+
+use Square\Pjson\JsonDataSerializable;
+
+/**
+ * A serializable ID wrapper class
+ */
+class PjsonId implements JsonDataSerializable
+{
+    public function __construct(protected string $value) { }
+
+    public function toJsonData(): string
+    {
+        return $this->value;
+    }
+
+    public static function fromJsonData($jd, array|string $path = []): static
+    {
+        return new static($jd);
+    }
+}