With today's update this `serverless.yml` no longer deploys:

```yaml
service: "localtest"

provider:
  name: "aws"
  runtime: "nodejs10.x"

functions:
  hello:
    handler: "handler.hello"
    events:
    - http:
        path: "/"
        method: "get"
        integration: "lambda-proxy"

plugins:
  - "serverless-localstack"

custom:
  localstack:
    stages:
      - "local"
```

The error on the localstack end seems to be that it cannot create `ApiGateway::RestApi` type resources:
```
2019-10-24T09:10:41:DEBUG:localstack.utils.cloudformation.template_deployer: Deploying resource type "ApiGateway::RestApi" id "ApiGatewayRestApi"
2019-10-24T09:10:41:DEBUG:localstack.utils.cloudformation.template_deployer: Request for creating resource type "ApiGateway::RestApi": create_rest_api {'name': 'local-localtest'}
2019-10-24T09:10:41:ERROR:localstack.services.cloudformation.cloudformation_starter: Unable to parse and create resource "ApiGatewayRestApi": argument of type 'NoneType' is not iterable
```

This is followed by repeated `TypeError` and then `KeyError`.
""" Convert data types in the "params" object, with the type defs
        specified in the 'types' attribute of "func_details". """
    types = func_details.get('types') or {}
    attr_names = types.keys() or []
    def cast(_obj, _type):