yii\authclient\OAuth2::createToken PHP Method

    protected function createToken(array $tokenConfig = [])
    {
        $tokenConfig['tokenParamKey'] = 'access_token';
        return parent::createToken($tokenConfig);
    }

 /**
  * Creates token from its configuration.
  * @param array $tokenConfig token configuration.
  * @return OAuthToken token instance.
  */
 protected function createToken(array $tokenConfig = [])
 {
     $tokenConfig['tokenParamKey'] = 'access_token';
     return parent::createToken($tokenConfig);
 }