title: Cannot read property 'authorizationUrl' of undefined
body: <p>Im trying to get consentUrl but getting "Cannot read property 'authorizationUrl' of undefined".</p>
  
  <p>Im using "xero-node": "^4.1.2"</p>
  
  <pre><code>const xero = new xero_node.XeroClient({
      clientId: "clientId",
      clientSecret: "clientSecret",
      redirectUris: ["redirectUrl"],
      scopes: "offline_access,openid".split(",")
  });
  </code></pre>
  
  <p>then inside async function i'm calling this:</p>
  
  <pre><code>let consentUrl = await xero.buildConsentUrl();
  </code></pre>
  
  <p>and it gives error : Cannot read property 'authorizationUrl' of undefined.</p>
  
  <p>Should I create url manually if this function is not supported. Need help thanks. </p>