sqs.changeMessageVisibility according to [this](https://docs.aws.amazon.com/AWSSimpleQueueService/latest/APIReference/API_ChangeMessageVisibility.html#API_ChangeMessageVisibility_Examples) makes a request directly to the Queue's URL rather than via the SQS Endpoint. (I'm already setting SQS endpoint to LOCALSTACK_HOSTNAME - makes no difference for this call)..

In localstack the queue URL host returned is by default set to the value of HOSTNAME_EXTERNAL, which I'm setting to localstack, but calling this method within a lambda, does not work and I get the error:

```
UnknownEndpoint: Inaccessible host: `localstack'. This service may not be available in the `us-east-1' region. 
```

So, how can I make the queue URL accessible from within a lambda using localstack? Effectively I need to make **http://localstack** accessible from within lambda.

I'm using the following cmd to start localstack:

```
LAMBDA_EXECUTOR=docker-reuse DEBUG=1 LAMBDA_REMOTE_DOCKER=0 DATA_DIR=/tmp/localstack/data HOSTNAME_EXTERNAL=localstack localstack start
```
return """
            <PostResponse>
                <Location>{protocol}://{host}/{encoded_key}</Location>
                <Bucket>{bucket}</Bucket>
                <Key>{key}</Key>
                <ETag>{etag}</ETag>
            </PostResponse>
            """.format(
            protocol=get_service_protocol(),
            host=config.HOSTNAME_EXTERNAL,
            encoded_key=urlparse.quote(key, safe=''),
            key=key,
            bucket=bucket_name,
            etag='d41d8cd98f00b204e9800998ecf8427f',
        )
    def get_forward_url(self, method, path, data, headers):