title: Cannot find 'SessionManager' in scope?
body: <p>I'm updating my code with RxAlamofire. I updated RxAlmofire with lastest version. How can i update this code <code>config.httpAdditionalHeaders = SessionManager.defaultHTTPHeaders</code> in</p>
  <pre><code>let config = URLSessionConfiguration.default
      config.httpAdditionalHeaders = SessionManager.defaultHTTPHeaders
  </code></pre>
  <p>I tried with <code>config.httpAdditionalHeaders = HTTPHeader.defaultUserAgent</code> but not success</p>