changed ApproximateFirstReceiveTimestamp and SentTimestamp to be returned in millis as per doco https://docs.aws.amazon.com/AWSSimpleQueueService/latest/APIReference/API_ReceiveMessage.html
changed ApproximateFirstReceiveTimestamp and SentTimestamp to be returned in millis as per doco https://docs.aws.amazon.com/AWSSimpleQueueService/latest/APIReference/API_ReceiveMessage.html

p4tin/GoAws