`id_token_signed_response_alg` should include `RS256`

[uvdsl]

Hi,
based on the input provided in uvdsl/solid-oidc-client-browser#14,

Pivot seems not to include RS256 as an option for id_token_signed_response_alg (see the openid configuration e.g. of solidcommunity.net).

This is related to the corresponding CSS issue, CommunitySolidServer/CommunitySolidServer#2055.

As mentioned there:

The OIDC Discovery Spec says

id_token_signing_alg_values_supported
REQUIRED. JSON array containing a list of the JWS signing algorithms (alg values) supported by the OP for the ID Token to encode the Claims in a JWT [JWT]. The algorithm RS256 MUST be included. ...

If you'd kindly add RS256 to the configuration, Pivot would maintain interoperability with NSS and TrinPod by following the OIDC spec.

Cheers
Christoph