Rostyslav Khoptiy

~~If anyone is interested I have my own PKCE implementation on [my fork](https://github.com/Ross65536/ex_oauth2_provider) while my [PR](https://github.com/danschultzer/ex_oauth2_provider/pull/91) gets reviewed.~~ EDIT: I'm no longer maintaining my fork

> Appendix B I'll see If I have time later for this. But feel free to contribute with the tests if you need it right away :)

the mix deps will need to be updated with the changes from the depended PR to make the tests pass

@danschultzer Could you take a look at this PR?

the mix deps will need to be updated with the changes from the depended PR to make the tests pass

I'm currently working on adding support for this using an introspection endpoint