Add /openid/token route

src/data/openid_config.rs

@@ -27,6 +27,9 @@ pub struct OpenIDConfig {
     /// 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. The value none MAY be supported, but MUST NOT be used unless the Response Type used returns no ID Token from the Authorization Endpoint (such as when using the Authorization Code Flow).
     pub id_token_signing_alg_values_supported: Vec<&'static str>,
 
+    /// OPTIONAL. JSON array containing a list of Client Authentication methods supported by this Token Endpoint. The options are client_secret_post, client_secret_basic, client_secret_jwt, and private_key_jwt
+    pub token_endpoint_auth_methods_supported: Vec<&'static str>,
+
     /// RECOMMENDED. JSON array containing a list of the Claim Names of the Claims that the OpenID Provider MAY be able to supply values for. Note that for privacy or other reasons, this might not be an exhaustive list.
     pub claims_supported: Vec<&'static str>,
 }