docs(CHANGELOG): Update CHANGELOG.md

Signed-off-by: -LAN- <laipz8200@outlook.com>

CHANGELOG.md

@@ -5,6 +5,13 @@ All notable changes to Dify will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.15.7] - 2025-04-25
+
+### Added
+
+- Added support for Amazon Bedrock Claude Sonnet 3.7 model (#18788)
+- Refined version compatibility logic in app DSL service
+
 ## [0.15.6] - 2025-04-22
 
 ### Security