Support passing a `nonce`

[nahoc]

Most other OIDC providers (Google, Facebook, Twitch) support passing a nonce that then gets encoded into the JWT.

Something like

    const authUrl = new URL("https://www.linkedin.com/oauth/v2/authorization");
    authUrl.searchParams.append("nonce","my_nonce");

It is necessary for my use-case, right now I cannot add a "Log in with LinkedIn" button because of this limitation. state is supported, but doesn't get encoded in the JWT.