fix axios config headers

[Christopher-md]

Hi, I faced this problem in version 1.0+

After refreshing the token, I was returning a request with the old configurations. When I looked in the network, after updating the token, the getUserInfo method was not displayed.

Solution: need to check if config.headers is not instance of AxiosHeaders

 if (!(config.headers instanceof AxiosHeaders)) {
      const defaultHeaders = config.headers && utils.merge(
          config.headers.common,
          config.headers[config.method]
      );

      defaultHeaders && utils.forEach(
          ['delete', 'get', 'head', 'post', 'put', 'patch', 'common'],
          function cleanHeaderConfig(method) {
            delete config.headers[method];
          }
      );

      config.headers = new AxiosHeaders(config.headers, defaultHeaders);
    }

Hope you fix it soon. Thanks

[Christopher-md]

Has been fixed in #5224