Update subscription-sequence.md

aw-design-diagram/subscription-sequence.md

+```mermaid
 sequenceDiagram
 participant PCM App
 participant OCM Admin
@@ -16,3 +17,4 @@ participant OCM Proof Manager
   PCM App ->> OCM Proof Manager: Responds with Proof Request.
   OCM Proof Manager ->> OCM Connection Manager Db: Changes the status of Connection to Trusted from Completed if proof verification is successful
   end
+```