feat: support chrome-headless-shell

[mathiasbynens]

Issue: #10736

[OrKoN]

I think it needs a npm run format

[mathiasbynens]

npm run format done!

[OrKoN]

also, npm run docs is needed since the API docs are changed

[mathiasbynens]

Docs pushed!

[OrKoN]

@mathiasbynens I have overlooked missing tests, let's add a test for the chrome-headless-shell browser-data and perhaps one test making sure it's actually installable?

[OrKoN]

also, it looks like the Firefox version has gone outdated so we need to bump it in the test files.