feat: add CHANGELOG

Signed-off-by: SuZhou-Joe <[email protected]>

CHANGELOG.md

@@ -28,6 +28,8 @@ Inspired from [Keep a Changelog](https://keepachangelog.com/en/1.0.0/)
 - [Multiple Datasource] Create data source menu component able to be mount to nav bar ([#6082](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/6082))
 - [Multiple Datasource] Handle form values(request payload) if the selected type is available in the authentication registry ([#6049](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/6049))
 - [Multiple Datasource] Add Vega support to MDS by specifying a data source name in the Vega spec ([#5975](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/5975))
+- [Workspace] Add a workspace client in workspace plugin ([#6094](https://github.com/opensearch-project/OpenSearch-Dashboards/pull/6094))
+
 
 ### 🐛 Bug Fixes