fixed#10 by implementing a flag in the response extensions that
instructs the middleware to clear the session. The flag is automatically
set when using the `OidcRpInitiatedLogout` as a responder.
improved documentation
modified example to reflect api changes
Updated the dependencies to the newest version.
Added `AsRef` and `Deref` traits to the extractors.
Moved the example from `README.md` to `examples/basic`.
Added a CI Pipeline.