[Devops] Stop forked repos running the `Publish` on `main` push

[seanpreston]

When you push to main on forked repos, our CI tries to run the Publish action:

We should disable this.

[adamsachs]

some very preliminary research points to the "proper" support for this functionality still being in the backlog for github: https://github.com/github/feedback/discussions/9098

this post seems to point to a potential solution with an 'if' conditional within each job: https://github.community/t/stop-github-actions-running-on-a-fork/17965/2

and it also mentions the settings that can be set on the side of the forked repo to disable actions (a mitigation, not really addressing the problem here).

i'm still new to github actions so please take my research with a grain of salt :)

[adamsachs]

interestingly, in testing this it seems that a user needs to now opt-in to enable actions on their forked repository (see screenshot). perhaps this is a good enough mitigation?

if not, then we can try to implement the 'if' conditional solution referenced above, but that doesn't feel very clean.

[adamsachs]

for what it's worth, i tried out the 'if' conditional workaround on a test fork repo: https://github.com/adamsachs/fidesops_forked_test/commit/2325c71302b0ba2ad112433afd6aaf5494291f73

and it seemed to work in that the action was skipped: https://github.com/adamsachs/fidesops_forked_test/actions/runs/2163901775