fix broken ipv6 listener

doc/debian/jitsi-meet/jitsi-meet.example

@@ -2,6 +2,7 @@ server_names_hash_bucket_size 64;
 
 server {
     listen 80;
+    listen [::]:80;
     server_name jitsi-meet.example.com;
 
     location ^~ /.well-known/acme-challenge/ {
@@ -17,6 +18,7 @@ server {
 }
 server {
     listen 443 ssl;
+    listen [::]:443 ssl;
     server_name jitsi-meet.example.com;
 
     ssl_protocols TLSv1 TLSv1.1 TLSv1.2;