Expose a way to log response headers

Describe the problem you’d like to have solved

I recently have been going back and fourth on a ticket with support regarding latency we were experiencing. I have been asked on multiple occasions by the support team to provide request ids that come back as a response header x-auth0-requestid. This is frustrating because this SDK does not expose a way to log these.

Describe the ideal solution

For my use case, I think the ideal solution would be to expose a way to add an interceptor to the OkHttp client. This would give consumer access to what they need (headers, etc) without the SDK being opinionated about what it should log and adding something that would need maintained by the SDK over time (the header names changing, etc).

If exposing the ability to add a custom interceptor is too much, it should be enough to expose the log level of the HttpLoggingInterceptor that is added to the OkHttp client today. The SDK sets the log level to Level.NONE currently.

Alternatives and current work-arounds

Additional information, if any

[jimmyjames]

The changes in #392 are included in v1.37.0, which will be available in Maven shortly. Thanks for the collaboration on this! 🙇

[dpromanko]

@jimmyjames I tested these changes locally with my application and it functions exactly as I would expect using LogLevel.HEADERS.