Use HTTP/2

[adabotonjic38]

Describe the bug
HTTP/2 of websites hosted on Siteground is not recognized by Lighthouse.

To Reproduce
Steps to reproduce the behavior:

1. Go to https://web.dev/measure/
2. Insert a website https://test.delittopergioco.it/
3. Click on "Run audit"
4. See error "Does not use HTTP/2 for all of its resources"

Expected behavior
If you look at the dev tools of chrome, you can see that there is http/2. So I would expect that also Lighthouse recognise it.

[robdodson]

Running the site through PSI I see the following:
https://developers.google.com/speed/pagespeed/insights/?url=https%3A%2F%2Ftest.delittopergioco.it%2F

When I look at the site locally with devtools I don't see anything using http/1.

Not sure if this is an issue with PSI (which web.dev/measure uses) or the site itself.

[connorjclark]

please follow #7326