SigningAlgs   []string `json:"id_token_signing_alg_values_supported"` // REQUIRED in OIDC
}

// openIDConfigJSON returns the JSON OIDC Discovery Doc for the service
// account issuer.
func openIDConfigJSON(iss, jwksURI string, keys []interface{}) ([]byte, error) {
	keyset, errs := publicJWKSFromKeys(keys)
	if errs != nil {
		return nil, errs
	}