SI-1692 - Updated README

Author: kmeretskyi

README.md

@@ -26,4 +26,9 @@ This is simple library for Braze REST API.
 ### Messages
 
 - [x] **POST** `/messages/send`
-    - [Braze API - Send Messages](https://www.braze.com/docs/api/endpoints/messaging/send_messages/post_send_messages)
+    - [Braze API - Send Messages](https://www.braze.com/docs/api/endpoints/messaging/send_messages/post_send_messages)
+
+### Campaigns
+
+- [x] **POST** `/campaigns/trigger/send`
+  - [Braze API - Send campaign messages](https://www.braze.com/docs/api/endpoints/messaging/send_messages/post_send_triggered_campaigns)