Update Date in Changelog (Azure#23111)

Author: sarangan12

sdk/search/search-documents/CHANGELOG.md

@@ -1,6 +1,6 @@
 # Release History
 
-## 11.3.0-beta.8 (unreleased)
+## 11.3.0-beta.8 (2022-09-06)
 
 - Added `core-http-compat` dependency
 - Enabled national cloud support for Azure Search SDK. Please refer [#22887](https://github.com/Azure/azure-sdk-for-js/pull/22887) for further details.