Display Baseline PWA requirements that LH can't test

[paulirish]

strawman from #1887:

Congrats, you're bonafide!

You've met the requirements for a baseline progressive web app*.

*Baseline PWAs require a few criteria that Lighthouse didn't test. 1) The site must work crossbrowser. 2) Each page must have a URL. 3) Transitions between pages dont feel janky. Read more here.

(Just an idea, I'm up for anything. Fake coming-soon audits could be fine too)

the 3 items are listed in internal doc https://goto.google.com/kwrck but are unchanged (so far) from the public baseline checklist.