docs: update release notes for v0.187.4

Signed-off-by: Doc Holiday <noreply@docholiday.ai>

Signed-off-by: Doc Holiday <doc@doc.holiday>

Author: sg-doc-holiday[bot]

RELEASE_NOTES.md

@@ -13,6 +13,10 @@ title: Release notes
 
 This release updates the published release history so the prior `v0.187.3` changes are included for reference.
 
+### Additional Changes
+
+* Updated the published release history to include the prior `v0.187.3` entry, making the recent release record easier to follow.
+
 ## v0.187.3
 
 - **Date:** 2026-07-07