I'm working on a GitHub app to allow me to keep my forks of public repositories in sync with the upstream. If I create my GitHub app and install it in my personal organisation, I can get webhook events delivered about any commits/branches is my fork, but is there a way to get my webhook to be able to get webhook notifications when something happens in the upstream repository?
eg, If I fork apache/commons-io (a public repo), I want to be able to receive webhook notifications whenever the master branch of apache/commons-io is updated so that I can keep the master branch in my fork updated (and other use-cases, not just this one). Obviously I can't ask the apache foundation to install my GitHub app so I was wondering whether there is a way to get read-only notifications on these public repos without having to resort to periodic polling to see if there are any updates to the upstream repository?
