Name of the resource
AWS::ApiGateway::Stage
Resource name
AWS::ApiGateway::Stage
Reference Link
https://docs.aws.amazon.com/AWSCloudFormation/latest/TemplateReference/aws-resource-apigateway-stage.html#cfn-apigateway-stage-deploymentid
Details
It is a required parameter though. See API docs.
And without it, you get the error during deployment:
Resource handler returned message: "DeploymentId cannot be empty" (RequestToken: d3e94518-cddb-c6d9-8743-f0cb5e8f8b59, HandlerErrorCode: InvalidRequest)