Update CHANGELOG.md with bearer token authentication feature

Co-authored-by: rujche <171773178+rujche@users.noreply.github.com>

Author: Copilot

sdk/keyvault/azure-security-keyvault-jca/CHANGELOG.md

@@ -3,6 +3,7 @@
 ## 2.11.0-beta.1 (Unreleased)
 
 ### Features Added
+- Added support for bearer token authentication via the `azure.keyvault.access-token` system property. This allows users to provide a pre-obtained access token for authentication, enabling multi-factor authentication scenarios without requiring client ID and client secret. Authentication priority order is: Managed Identity > Access Token > Client Credentials.
 
 ### Breaking Changes