Rename plugins to libs and update all file references

libs/stripe-php/lib/Events/UnknownEventNotification.php

@@ -0,0 +1,25 @@
+<?php
+
+namespace Stripe\Events;
+
+use Stripe\V2\Core\EventNotification;
+
+/**
+ * A class representing an EventNotification that the SDK doesn't have types for.
+ *
+ * @property null|\Stripe\RelatedObject $related_object Object containing the reference to API resource relevant to the event.
+ */
+class UnknownEventNotification extends EventNotification
+{
+    public $related_object;
+
+    /**
+     * Retrieve the event's related object from the Stripe API, if one exists. Returns null otherwise.
+     *
+     * @return null|\Stripe\StripeObject
+     */
+    public function fetchRelatedObject()
+    {
+        return parent::fetchRelatedObject();
+    }
+}