haproxy: enable HTTP/2 support

Author: lionelnicolas

etc/haproxy/haproxy.cfg

@@ -43,8 +43,8 @@ backend backend_haproxy_stats
 	server stats 127.0.0.1:8081
 
 frontend frontend_http_reverse_proxy
-	bind *:80
-	bind *:443 ssl crt /run/haproxy/certs
+	bind *:80 alpn h2,http/1.1
+	bind *:443 ssl crt /run/haproxy/certs alpn h2,http/1.1
 	mode http
 
 	# handle haproxy statistics page