Update changelog for integrations/amazon_bedrock (#2122)

Co-authored-by: anakin87 <44616784+anakin87@users.noreply.github.com>

Author: HaystackBot

integrations/amazon_bedrock/CHANGELOG.md

@@ -1,5 +1,12 @@
 # Changelog
 
+## [integrations/amazon_bedrock-v3.9.1] - 2025-07-31
+
+### 🐛 Bug Fixes
+
+- `AmazonBedrockChatGenerator` - fix bug with streaming + tool calls with no arguments (#2121)
+
+
 ## [integrations/amazon_bedrock-v3.9.0] - 2025-07-29
 
 ### 🚀 Features