Update changelog link to upstream PR palantir#1661

Agent-Logs-Url: https://github.com/AntonLem/palantir-java-format/sessions/c664dcf3-7c62-4138-9429-da1575c6eba2

Co-authored-by: AntonLem <2189039+AntonLem@users.noreply.github.com>

Author: Copilot

changelog/@unreleased/pr-4.v2.yml

@@ -2,4 +2,4 @@ type: improvement
 improvement:
   description: Add JHarmonizer into the README as a third-party integration
   links:
-  - https://github.com/AntonLem/palantir-java-format/pull/4
+  - https://github.com/palantir/palantir-java-format/pull/1661