Missing runtime for snippet Amazon SQS partial batch response Lambda function

[mkovel]

Wrong response format:

    return {
        statusCode: 200,
        body: JSON.stringify({ batchItemFailures }),
    };

with proxy response format not working. It knowledge cost me a day. ((

    return { 
        batchItemFailures
    };

[matthewskahn]

Should be fixed now that #156 is merged