in api/src/main/scala/com/gu/adapters/store/Store.scala [246:254]
def presignedUrl(
bucket: String,
key: String,
expiration: DateTime = DateTime.now(DateTimeZone.UTC).plusMinutes(20)
): Either[Error, URL] = {
val request = new GeneratePresignedUrlRequest(bucket, key)
request.setExpiration(expiration.toDate)
handleIoErrors(client.generatePresignedUrl(request))
}