add private beta flag on PM request [netlify-build]

Author: pwseg

src/connections/destinations/catalog/actions-webhook-extensible/index.md

@@ -11,6 +11,9 @@ Segment's Extensible Webhooks destination lets you send custom data payloads to
 
 Segment maintains this destination. For any issues, [contact Segment Support]([email protected]).
 
+> info "Private beta"
+> The Extensible Webhooks is in private beta, and Segment is actively working on this feature. Some functionality may change before it becomes generally available.
+
 ## Overview
 
 To set up and use Extensible Webhooks, you'll follow these four main stages: