Apache doesn’t have to support it. The Chrome extension reads the HTTP headers to determine that.
Another method is simply to look at the network tab > headers > response headers > view source in Chrome or Firefox. There the headers can be seen. It should read “HTTP/2” or some sort I can’t recall right now.
Easiest: You can use curl -I <your site> which will put the HTTP response as the first line.
HTTP/2.0 200
server:nginx
date:Fri, 29 Apr 2016 14:31:40 GMT
content-type:text/html; charset=utf-8
content-length:7629
last-modified:Thu, 07 Apr 2016 02:41:08 GMT
....