docs: update changelog for integrations/amazon_bedrock (#2291)

* Update changelog for integrations/amazon_bedrock

* Update CHANGELOG.md

---------

Co-authored-by: Amnah199 <13835656+Amnah199@users.noreply.github.com>
Co-authored-by: Amna Mubashar <amnahkhan.ak@gmail.com>

Author: HaystackBot

integrations/amazon_bedrock/CHANGELOG.md

@@ -1,5 +1,11 @@
 # Changelog
 
+## [integrations/amazon_bedrock-v4.2.0] - 2025-09-19
+
+### 🚀 Features
+
+- Add a new `S3Downloader` component (#2192)
+
 ## [integrations/amazon_bedrock-v4.1.0] - 2025-09-19
 
 ### 🚀 Features