add buffer size to proxy_site.j2 template; update proxy_site_defs.yml as a result

templates/proxy_site.j2

@@ -63,6 +63,12 @@ location /nginx_status {
 
     # re-write redirects to http as to https
     proxy_redirect http:// https://;
+
+
+    # set buffer sizes (for keycloak user reg)
+    proxy_buffer_size 128k;
+    proxy_buffers 4 256k;
+    proxy_busy_buffers_size 256k;
   }
 
 {% if item.key == "seafile.thezengarden.net" %}