Correlation IDs in introspect flow

[bhedia]

Hello,

Is it possible to configure the OIDC plugin to forward a correlation ID to the OIDC provider from Kong (from the incoming request) in the introspect flow?

That way, if there is a failure in the introspection, internal engineers can use the correlation ID to track where the request failed, and why.

[bhedia]

Added a PR for this functionality:
#214