add error when empty metric values to changelog

Signed-off-by: Rob Pickerill <r.pickerill@gmail.com>

CHANGELOG.md

@@ -69,6 +69,7 @@ Here is an overview of all new **experimental** features:
 - **General**: Add support for cross tenant/cloud authentication when using Azure Workload Identity for TriggerAuthentication ([#5441](https://github.com/kedacore/keda/issues/5441))
 - **Metrics API Scaler**: Add support for various formats: json, xml, yaml, prometheus ([#2633](https://github.com/kedacore/keda/issues/2633))
 - **MongoDB Scaler**: Add scheme field support srv record ([#5544](https://github.com/kedacore/keda/issues/5544))
+- **AWS CloudWatch Scaler**: Add support for errorWhenMetricValuesEmpty ([#5352](https://github.com/kedacore/keda/issues/5352))
 
 ### Fixes