[mananaysiempre]

GitHub has per-repo feeds for commits and a private feed for all your events[1], but not for issues or discussions, apparently[2]. Of course, you can always roll your own using the API, a web server, and a cron job, even if it is a bit inelegant.

[1] https://webapps.stackexchange.com/q/20535

[2] https://github.com/github/feedback/discussions/31