Set X-Forwarded-Proto on federation requests

roles/matrix-nginx-proxy/templates/nginx/conf.d/matrix-domain.conf.j2

@@ -241,6 +241,7 @@ server {
 
 		proxy_set_header Host $host;
 		proxy_set_header X-Forwarded-For $remote_addr;
+		proxy_set_header X-Forwarded-Proto $scheme;
 
 		client_body_buffer_size 25M;
 		client_max_body_size {{ matrix_nginx_proxy_proxy_matrix_federation_api_client_max_body_size_mb }}M;