Unable to add more than 1 responses to apigw.AwsIntegration

[jameszh]

SelectionPattern is in the options block see aws-cdk doc as opposed to
in the integrationResponses cloudformation doc,

In the following code example, the syntax is correct, but it doesn't work as expected.

const successIntegration = new apigw.AwsIntegration({
    service: 'states',
    action: 'SendTaskSuccess',
    options: {
        credentialsRole: apigwRole,
        passthroughBehavior: apigw.PassthroughBehavior.WhenNoTemplates,
        requestTemplates: {
            "application/json": "{\n   \"output\": \"{ \\\"result\\\": \\\"Confirmed succeed\\\" }\",\n   \"taskToken\": \"$input.params('taskToken')\"\n}"
        },
        integrationResponses: [

            {
                statusCode: "200",
                responseTemplates: {"application/json": "{\n \"result\": \"It is a success.\"\n }"}
            },
            {
                statusCode: "503",
                responseTemplates: {"application/json": "{\n \"result\": \"Invalid request.\"\n }"}
            }
        ],
        selectionPattern: "200"
    }
});