change log for 4.19.0-beta release' (Azure#23887)

Co-authored-by: annie-mac <annie-mac@DESKTOP-62QAK4R.redmond.corp.microsoft.com>

Author: xinlian12

sdk/cosmos/azure-cosmos/CHANGELOG.md

@@ -1,7 +1,8 @@
 ## Release History
 
-## 4.19.0-beta.1 (Unreleased)
-
+### 4.19.0-beta.1 (2021-09-02)
+#### Key Bug Fixes
+* Added support to switch off IO thread for response processing.
 
 ### 4.18.0 (2021-08-16)
 > [!IMPORTANT]

sdk/cosmos/azure-spring-data-cosmos/CHANGELOG.md

@@ -1,7 +1,11 @@
 ## Release History
 
-## 3.11.0-beta.1 (Unreleased)
+### 3.11.0-beta.1 (2021-09-02)
+#### New Features
+* Updated `azure-cosmos` to version 4.19.0-beta.1.
 
+#### Key Bug Fixes
+* Fixed spring data cosmos query plan caching.
 
 ### 3.10.0 (2021-08-16)
 > [!IMPORTANT]