Tags attached to an IAM user are not saved. Create a user with attached tags. The response from the create user doesn't include the tags and when you run a GetUser the tags are not included.
```
aws-sdk-swift % aws --endpoint-url http://localhost:4593 iam create-user --user-name test-user --tags Key=test,Value=hello
```
produces output
```
{
    "User": {
        "Path": "/",
        "UserName": "test-user",
        "UserId": "peldynzrvm2tofi6nmmr",
        "Arn": "arn:aws:iam::000000000000:user/test-user",
        "CreateDate": "2019-10-23T08:46:31.305Z"
    }
}
```
The GetUser call produces exactly the same output
```
aws --endpoint-url http://localhost:4593 iam get-user --user-name test-user
```


I am running localstack as follows
```
docker run -d -p 4593:4593 -e SERVICES='iam' localstack/localstack
```
self.iam_client = aws_stack.connect_to_service('iam')
    def test_run_kcl_with_iam_assume_role(self):
        env_vars = {}
        if os.environ.get('AWS_ASSUME_ROLE_ARN'):
            env_vars['AWS_ASSUME_ROLE_ARN'] = os.environ.get('AWS_ASSUME_ROLE_ARN')
            env_vars['AWS_ASSUME_ROLE_SESSION_NAME'] = os.environ.get('AWS_ASSUME_ROLE_SESSION_NAME')
            env_vars['ENV'] = os.environ.get('ENV') or 'main'
            def process_records(records):
                print(records)
            
            stream_name = 'test-foobar'
            kinesis_connector.listen_to_kinesis(
                stream_name=stream_name,
                listener_func=process_records,
                env_vars=env_vars,
                kcl_log_level=logging.INFO,
                wait_until_started=True
            )
    def test_attach_iam_role_to_new_iam_user(self):
        test_policy_document = {