[Feature request] Discriminated unions on status for error or success responses

How would the swagger-typescript-api team feel about having the `status` from the response as a typescript union discriminant where rest of the props would be defined based on its value?

For example, if the `swagger.json` file contains this for a given api call -

```json
"responses": {
"200": {
"description": "Resource is successfully created.",
"schema": { "$ref": "#/definitions/ResourceSuccessResponse" }
},
"400": {
"description": "Create resource request has invalid fields.",
"schema": { "$ref": "#/definitions/ErrorResponse" }
},
"401": {
"description": "Create resource request has invalid user credentials.",
"schema": { "$ref": "#/definitions/ErrorResponse" }
},
"409": {
"description": "Resource name already exists.",
"schema": { "$ref": "#/definitions/ErrorResponse" }
}
}
```

hypothetically the response could be of this format -

```ts
type HttpResponseType = {
status: Status,
data: ResponseData
}

type ResourceCreationResponse =
| HttpResponseType<200, ResourceSuccess>
| HttpResponseType<400, ErrorResponse>
| HttpResponseType<401, ErrorResponse>
| HttpResponseType<409, ErrorResponse>

type ResourceSuccess = {
resource: string
}

type ErrorResponse = {
code: number
message: string
}

declare const a: MyApiCallResponseType;

if(a.status === 200) {
console.log(a.data) // `a.data` is of type ResourceSuccess now
}
```

This could also be an option if not the default.

I would be willing to make a PR for this if this seems like a good idea. It definitely makes the resulting types stronger in my experience with slight flexibility cost.