"Cookie Inspector" Chrome Extension no longer exists.

I'm a longtime user of Backstop, thank you! Recently I needed to test pages requiring a login and noticed that my Cookie Inspector extension had gone missing from Chrome. I found the link to it in your README file and discovered it's returning a 404 error. So apparently the extension no longer exists?

I tried [Export cookie JSON file for Puppeteer](https://chrome.google.com/webstore/detail/%E3%82%AF%E3%83%83%E3%82%AD%E3%83%BCjson%E3%83%95%E3%82%A1%E3%82%A4%E3%83%AB%E5%87%BA%E5%8A%9B-for-puppet/nmckokihipjgplolmcmjakknndddifde?hl=en) and it worked great. Possibly even a little easier than the old plugin. But I wanted to see what others are using? Perhaps there's something better?

I'm happy to update the README.md and submit a PR. But I'm not sure if all the steps in the contrib guidelines would need to be followed since it's just a README change?