Request offline_access in the concierge with supervisor demo

It's a generic config and not OIDC provider specific
but since most providers require it it seems like the
best default.

site/content/docs/tutorials/concierge-and-supervisor-demo.md

@@ -135,7 +135,7 @@ to authenticate federated identities from the Supervisor.
      claims:
        username: email
      authorizationConfig:
-       additionalScopes: ['email']
+       additionalScopes: ['email', 'offline_access']
      client:
        secretName: my-oidc-identity-provider-client
    EOF