Improvements
------------
* Bump `httpx-oauth >=0.4,<0.11`
* With `httpx-oauth >= 0.10`, the OAuth2 client may be not able to return an email address depending on the OAuth Provider. In this case, the error `OAUTH_NOT_AVAILABLE_EMAIL` is raised during `/callback`. [[Documentation](https://fastapi-users.github.io/fastapi-users/10.2/usage/routes/#get-callback)]
* Enable Python 3.11 support in CI