.dev domain is empty

When BackstopJS creates a screenshot of a .dev domain in my case the screenshot is empty. The reason is probably because you need to enter "badidea" respectively "thisisunsafe" before you can view the page (since there's no valid SSL certificate). Is there a workaround?

I have tried:

```javascript
"casperFlags": [
"--ignore-ssl-errors=true",
"--ssl-protocol=any"
],
"engineOptions": {
"chromeFlags": [
"--ignore-certificate-errors"
]
}
```