title: google api refresh token returns null with react-google-login
body: <p>Refresh token is always null, I plowed through the documentation and did serval experiments. But i could not get the refreshToken to renew the access token for offline use.</p>
  
  <p>I'm using react-google-login to get my offline token. I assume this is correctly set up.</p>
  
  <p>Just in case here's the setup:</p>
  
  <pre><code>    &lt;GoogleLogin
          clientId="***"
          buttonText="Login"
          accessType="offline"
          responseType="code"
          scope={"https://www.googleapis.com/auth/calendar"}
          onSuccess={responseGoogle}
          onFailure={responseGoogle}
      /&gt;
  </code></pre>
  
  <p>But when I'm using the authorization code only an access token is returned that is valid for 3600 seconds. I can use the accessToken to access the api. But it seems the refresh token is not provided.</p>
  
  <pre><code>    GoogleTokenResponse tokenResponse =
              new GoogleAuthorizationCodeTokenRequest(
                      new NetHttpTransport(),
                      JacksonFactory.getDefaultInstance(),
                      "https://www.googleapis.com/oauth2/v4/token",
                      clientSecrets.getDetails().getClientId(),
                      clientSecrets.getDetails().getClientSecret(),
                      AUTH_CODE,
                      REDIRECT_URL)
                      .execute();
  
  
  
      String refreshToken = tokenResponse.getRefreshToken();
      String accessToken = tokenResponse.getAccessToken();
  </code></pre>
  
  <p>Any clue what is wrong?</p>