Update authlib to 0.10

[pyup-bot]

This PR updates authlib from 0.9 to 0.10.

Changelog

0.10

-------------------

**Released on Oct 12, 2018.**

The most important change in this version is grant extension system. When
registering a grant, developers can pass extensions to the grant::

 authorization_server.register_grant(GrantClass, [extension])

Find Flask :ref:`flask_oauth2_grant_extensions` implementation.

RFC implementations and updates in this release:

- RFC8414: OAuth 2.0 Authorization Server Metadata
- RFC7636: make CodeChallenge a grant extension :ref:`specs/rfc7636`
- OIDC: make OpenIDCode a grant extension

Besides that, there are other improvements:

- Export ``save_authorize_state`` method on Flask and Django client
- Add ``fetch_token`` to Django OAuth client
- Add scope operator for ``require_oauth`` :ref:`flask_oauth2_multiple_scopes`
- Fix two OAuth clients in the same Flask route :gh:`PR85`

**Deprecate Changes**: find how to solve the deprecate issues via https://git.io/fAmW1

Links

• PyPI: https://pypi.org/project/authlib
• Changelog: https://pyup.io/changelogs/authlib/
• Homepage: https://authlib.org/