BasePathMapping

Hello, I'm trying to use a custom domain but I have the following error:

I'm using example: basic-starter-api-gateway-v2-typescript/

```
CREATE_FAILED AWS::ApiGateway::BasePathMapping MyApiBasePathMapping

Resource handler returned message:
Mixing of REST APIs and HTTP APIs
on the same domain name can only be
accomplished through API Gateway's
V2 DomainName interface. Currently,
WebSocket APIs can only be attached
to a domain name with other
WebSocket APIs. This must also
occur through API Gateway's V2
DomainName interface. (Service:
ApiGateway, Status Code: 400,
Request ID: 5187005f-3413-47bb-b777
-6c98784001d0
```

Reproduce the failure using basic-starter-api-gateway-v2-typescript/ and inspect the generated AWS::ApiGateway::BasePathMapping resource for the custom domain. Start by checking how the example configures API Gateway domain mappings; done means the example deploys successfully without the REST/HTTP API mixing error.

索引モデルが issue の本文から書いたものです。