doc: add note for subscription (#12607)

Author: anshbansal

docs/managed-datahub/release-notes/v_0_3_8.md

@@ -63,6 +63,7 @@ Recommended CLI/SDK
     - Hardened structured properties feature by supporting broken references and adding better validation to the ID/qualified name
     - Hardened forms feature by supporting invalid / unresolvable references
     - Recurrent metadata sharing: Any assets shared between DataHub assets will be re-shared automatically once per day. 
+    - On entity page by hovering over subscribe button you can see list of subscribers of the entity.
 
 
 - Platform