Update CHANGELOG.md for Release v1.15.3

Author: web-flow

CHANGELOG.md

@@ -6,6 +6,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 
 ## [Unreleased]
 
+## [1.15.3] - 2025-07-07
+
 ### Changed
 
 - Pin `nrfutil device` to `2.12.2`.
@@ -184,7 +186,8 @@ All below changes are related to the ncs-zephyr Docker image:
 
 - Vanilla Zephyr Dockerfiles and publish workflows.
 
-[unreleased]: https://github.com/IRNAS/irnas-docker-software/compare/v1.15.2...HEAD
+[unreleased]: https://github.com/IRNAS/irnas-docker-software/compare/v1.15.3...HEAD
+[1.15.3]: https://github.com/IRNAS/irnas-docker-software/compare/v1.15.2...v1.15.3
 [1.15.2]: https://github.com/IRNAS/irnas-docker-software/compare/v1.15.1...v1.15.2
 [1.15.1]: https://github.com/IRNAS/irnas-docker-software/compare/v1.15.0...v1.15.1
 [1.15.0]: https://github.com/IRNAS/irnas-docker-software/compare/v1.14.0...v1.15.0
@@ -207,5 +210,4 @@ All below changes are related to the ncs-zephyr Docker image:
 [1.2.0]: https://github.com/IRNAS/irnas-docker-software/compare/v1.1.0...v1.2.0
 [1.1.0]: https://github.com/IRNAS/irnas-docker-software/compare/v1.0.1...v1.1.0
 [1.0.1]: https://github.com/IRNAS/irnas-docker-software/compare/v1.0.0...v1.0.1
-[1.0.0]:
-  https://github.com/IRNAS/irnas-docker-software/compare/b08044e0137bcbbf5f060545de6b2d2a9f1ee8d8...v1.0.0
+[1.0.0]: https://github.com/IRNAS/irnas-docker-software/compare/b08044e0137bcbbf5f060545de6b2d2a9f1ee8d8...v1.0.0