https://github.com/localstack/localstack/blob/e7efc768a20e75feafe3702a5a6e477a233feff2/localstack/utils/aws/aws_stack.py#L904

```
File "/usr/local/lib/python3.8/site-packages/localstack/services/generic_proxy.py", line 50, in <module>
from localstack.utils.aws import aws_stack
File "/usr/local/lib/python3.8/site-packages/localstack/utils/aws/aws_stack.py", line 904, in <module>
) -> dict[str, str]:
TypeError: 'type' object is not subscriptable
```

Please fix to `Dict[str, str]`
if is_local_env(env):
                endpoint_url = get_local_service_url(service_name)
                verify = False
            backend_env_name = "%s_BACKEND" % service_name.upper()
            backend_url = os.environ.get(backend_env_name, "").strip()
            if backend_url:
                endpoint_url = backend_url
        
        if service_name == "s3":
            if re.match(r"https?://localhost(:[0-9]+)?", endpoint_url):
                endpoint_url = endpoint_url.replace("://localhost", "://%s" % get_s3_hostname())
        
        boto_session = get_boto3_session(cache=cache)
        boto_config = config or botocore.client.Config()
        boto_factory = boto_session.client if client else boto_session.resource
        
        
        boto_config.max_pool_connections = MAX_POOL_CONNECTIONS
        new_client = boto_factory(
            service_name,
            region_name=region,
            endpoint_url=endpoint_url,
            verify=verify,
            config=boto_config,
            **kwargs,
        )
        
        
        if client and internal:
            def _add_internal_header(request, **kwargs):