Update CHANGELOG.md for hashicorp#40031

CHANGELOG.md

@@ -9,6 +9,10 @@ NOTES:
 * provider: validation of arguments implementing the custom `ARNType` will properly surface validation errors ([#40008](https://github.com/hashicorp/terraform-provider-aws/issues/40008))
 * resource/aws_api_gateway_stage: `deployment_id` was added to `canary_settings` as a `required` attribute. This breaking change was necessary to make `canary_settings` functional. Without this change all canary traffic was routed to the main deployment ([#39929](https://github.com/hashicorp/terraform-provider-aws/issues/39929))
 
+FEATURES:
+
+* **New Data Source:** `aws_spot_datafeed_subscription` ([#39647](https://github.com/hashicorp/terraform-provider-aws/issues/39647))
+
 ENHANCEMENTS:
 
 * data-source/aws_batch_job_definition: Add `init_containers`, `share_process_namespace`, and `image_pull_secrets` attributes ([#40019](https://github.com/hashicorp/terraform-provider-aws/issues/40019))