[REQ] [Java] [okhttp-gson] Allow overriding tokenUrl in ApiClient constructor

Is your feature request related to a problem? Please describe.

I have an openapi spec with a security section like:

  securitySchemes:
    mySecurityScheme:
      type: oauth2
      flows:
        clientCredentials:
          tokenUrl: https://example.com/token

I want to override tokenUrl at runtime. Currently the generated ApiClient class does not have a constructor or setter to allow overriding this value.

Describe the solution you'd like

A new ApiClient constructor that allows specifying tokenUrl.

The closest existing constructor is:

public ApiClient(String basePath, String clientId, String clientSecret, Map<String, String> parameters)

We could have a new constructor with this signature:

public ApiClient(String basePath, String clientId, String clientSecret, String tokenUrl, Map<String, String> parameters)

(could possibly use URI instead of String for tokenUrl).

Describe alternatives you've considered

My current workaround is to extend ApiClient and create the new constructor in the subclass.

Start by locating the generated Java okhttp-gson ApiClient and its existing constructor with basePath, clientId, clientSecret, and parameters. Add the requested constructor path so tokenUrl can be supplied at runtime, then verify that generated clients accept the value while preserving the existing constructor behavior.