Update docs/src/release_notes.rst

Co-authored-by: moritzkiefer-da <45630097+moritzkiefer-da@users.noreply.github.com>
Signed-off-by: Pasindu Tennage <pasindu.tennage@digitalasset.com>

Author: pasindutennage-da

docs/src/release_notes.rst

@@ -104,7 +104,7 @@
 
   - Validator
 
-    - Expose ``/holdings/summary`` endpoint from scan proxy
+    - Expose ``/v0/holdings/summary`` endpoint from scan proxy
 
 .. release-notes:: 0.5.6