Update ChangeLog.md

Author: wyunchi-ms

src/IotCentral/IotCentral/ChangeLog.md

@@ -18,8 +18,6 @@
         - Additional information about change #1
 -->
 ## Upcoming Release
-
-## Version 1.0.0
 * Stable release version, updated to IoT Central .NET Management Plane SDK version 4.0.0. 
 * This change introduces support for System-Assigned Managed Identities, removes support for geographic locations (e.g., 'unitedstates'), and removes support for legacy S1 sku.