title: Error: page.setRequestInterception is not a function
body: <p>I could not set viewport with pa11y.I'm getting Error.</p>
  
  <pre><code>{
  "defaults": {
      "timeout": 1000,
      "page": {
          "viewport": {
              "width": 320,
              "height": 480
          }
      }
  },
  "urls": [
      "https://sonymobile.com/gb",
      "https://sonymobile.com/gb/products/phone"
  ]
  </code></pre>
  
  <p>}</p>
  
  <p>Some details are here :</p>
  
  <p><img src="https://i.stack.imgur.com/5Xr2W.png" alt=""></p>