What is it that is missing from discourse in this regard? Can discourse be improved to meet your needs so you don’t need to use github at all?
You mention pull requests, so maybe the need is for the ability to request changes that are then reviewed and approved by someone else before a change is finalized? I guess you could do this in a “discourse way” by replying to the post to request a review or by assigning it to someone after you make the change. I have had some success with setting a topic timer to auto-delete replies, so the topic doesn’t get bogged down by lots of little replies.
Another idea would be to use the policy plugin. A group could be notified that a topic was changed and requested to confirm they read and agree to the change.
All that said, I think this is a pretty sweet idea and I’d like to see it implemented. I can see this being useful even for meta! We have many topics here about github repos and it would be nice to see updates to those repo readme.md files in the OP so they don’t have to be maintained in two places.
For Discourse for Teams it could be a useful feature as well, so that teams who use github heavily can also still use Teams as their “single source of truth” for reference, without everyone having to also log into their github all the time. I guess it could be part of or a companion to the code review plugin?