Return mocked value in specified format

[javier-sierra-sngular]

It would be nice if the application returns the mocked data, taking into account the format parameter (if specified).

https://spec.openapis.org/oas/v3.1.0#dataTypeFormat
https://ajv.js.org/packages/ajv-formats.html#formats

Currently, type: string is always returning 'string' regardless of the specified format.

If the type is string and the format is date, a more appropriate response would be '2023-11-17'.

I am going to link a PR to this issue.

Thanks