Extend auto-update check to the fetch API

The [fetch API](https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API/Using_Fetch) and [XHR](https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest) are different. The example app uses `fetch` so we can't trigger the auto update functionality without a change. Realistically we should instrument both.