this updates the authorization code flow per https://datatracker.ietf.org/doc/html/rfc6749#section-4.1.3 & https://datatracker.ietf.org/doc/html/rfc6749#section-2.3.1
google also supports client_secret_basic which is the sending of client id, client secret via request headers per https://accounts.google.com/.well-known/openid-configuration
this updates the authorization code flow per https://datatracker.ietf.org/doc/html/rfc6749#section-4.1.3 & https://datatracker.ietf.org/doc/html/rfc6749#section-2.3.1
google also supports `client_secret_basic` which is the sending of client id, client secret via request headers per https://accounts.google.com/.well-known/openid-configuration