Use latest oauth2-server package
This MR depends on !5 (merged). To pull PKCE PR, I forked oauth2-server and rebased its dev branch onto PKCE PR branch.
@bombkyu oauth2-server's dev branch includes many new features. You should test the followings before merging this.
- OAuth 2.0 Token Revocation https://tools.ietf.org/html/rfc7009
- OAuth 2.0 Implicit Grant https://tools.ietf.org/html/rfc6749#section-4.2
- Proof Key for Code Exchange by OAuth Public Clients https://tools.ietf.org/html/rfc7636
Don't be afraid. Ping me when you start the review.