Added an example code

example/main.php

@@ -0,0 +1,18 @@
+<?php
+declare(strict_types=1);
+use Gitea\{PushEvent};
+
+/**
+ * Handles the payload of a Gitea push event.
+ * @return PushEvent The parsed payload.
+ * @throws UnexpectedValueException The request headers or the request body are invalid.
+ */
+function main(): PushEvent {
+  if (!isset($_SERVER['HTTP_X_GITEA_DELIVERY']) || !isset($_SERVER['HTTP_X_GITEA_EVENT']))
+    throw new UnexpectedValueException('Invalid payload data.');
+
+  $data = json_decode((string) file_get_contents('php://input'));
+  if (!is_object($data)) throw new UnexpectedValueException('Invalid payload data.');
+
+  return PushEvent::fromJson($data);
+}