Add missing fetchSubscriptionSchedules in Gateway (#187)

Author: AntoineLemaire

src/Gateway.php

@@ -233,6 +233,17 @@ public function cancelSubscription(array $parameters = array())
         return $this->createRequest('\Omnipay\Stripe\Message\CancelSubscriptionRequest', $parameters);
     }
 
+    /**
+     * Fetch Schedule Subscription
+     *
+     * @param array $parameters
+     * @return \Omnipay\Stripe\Message\FetchSubscriptionSchedulesRequest
+     */
+    public function fetchSubscriptionSchedules(array $parameters = array())
+    {
+        return $this->createRequest('\Omnipay\Stripe\Message\FetchSubscriptionSchedulesRequest', $parameters);
+    }
+
     /**
      * Fetch Event
      *