Gogs shouldn't provide the nginx default_server

roles/service-gogs/templates/gogs_nginx.conf.j2

@@ -1,6 +1,6 @@
 server {
-  listen          443 ssl http2 default_server;
-  listen          [::]:443 ssl http2 default_server;
+  listen          443 ssl http2;
+  listen          [::]:443 ssl http2;
   server_name     {{ gogs_domain }};
 
   include /etc/nginx/ssl.conf;