Fix swagger nxx response

[climba03003]

Resolve: #250

Caption from swagger
To define a range of response codes, you may use the following range definitions: 1XX, 2XX, 3XX, 4XX, and 5XX. If a response range is defined using an explicit code, the explicit code definition takes precedence over the range definition for that code.

I do not introduce a new option as @Eomm suggestion. It will also not throwing error because it may break someone code.

Behavior for Swagger

• When I see Nxx status code, transform it to 200 status code.
• If we find conflict of 200 status code, drop the transformed one as it is more general response.
• Append the transformed status code to response.

Behavior for OpenAPI

• All Nxx status code will enforce upper case.
• Append the transformed status code to response.

Checklist

• run npm run test and npm run benchmark
• tests and/or benchmarks are included
• documentation is changed or added
• commit message and code follows the Developer's Certification of Origin
  and the Code of conduct

[mcollina]

lgtm

[mcollina]

Can you please add a unit test?

[mcollina]

lgtm