Allow custom CA bundle to be set for the whole OAuth2Session and being registered using oauth.register()

[hscholz]

Is your feature request related to a problem? Please describe.

I'm having a flask application which is integrating via OIDC with an OIDC provider which has a custom certificate. Currently there is no way to provide a CA bundle for RemoteApp.load_server_metadata().

Describe the solution you'd like

Enable the configuration of the CA bundle for the whole OAuth2Session and the RemoteApp via OAuth.register, e.g.

from authlib.integrations.flask_client import OAuth

oauth = OAuth(app)
client = oauth.register(
    name="oauth",
    server_metadata_url=f'{app.config["OAUTH_DOMAIN"]}/.well-known/openid-configuration',
    client_kwargs={"scope": "openid email profile", "verify": "/path/to/ca_bundle/cert.pem"},
)

[dbkegley]

Are there any workaround for this? I'm using the starlette integration and would like to specify the ca bundle for all httpx requests