Hi Saqib, I'll check and update the extension soon. The last time we checked with Gutenberg, we had a technical difficulty that we haven't resolved yet. Let us check again.
I've just updated the extension to make it works with Gutenberg. However, there's some limitation in Gutenberg, it only supports the template and post_format rules. Other rules are still not supported and need to wait for update from Gutenberg. I'll update the extension when it's done.