Hi Elsie! I do think you want a new feature topic here because the github plugin you are referring to is not the code review plugin.
I can see you are super keen. I believe adding support for issues to Discourse Code Review is PR welcome, but am not sure. If you could lay out here in some more detail what you have in mind, maybe someone in the community can pick it up. If you have a budget for it, you can also post it to marketplace.