Update CHANGELOG.md

Author: desokroshan

CHANGELOG.md

@@ -7,6 +7,11 @@
 * **AWS IoT**
   * AWS IoT SDK for Android now supports connecting your devices to AWS IoT Core using Persistent Sessions. Please look at [this blog](https://aws.amazon.com/about-aws/whats-new/2019/01/aws-iot-core-now-enables-customers-to-store-messages-for-disconnected-devices/) for more details.
 
+### Misc. Updates
+
+* Model updates for the following services
+  * Amazon Comprehend
+
 ### Bug Fixes
 
 * **Amazon Cognito Auth**