CI: fix macOS jobs to not run on MR from forks
My except: external_pull_requests
is not right.
See !1161 (merged) and https://gitlab.com/gitlab-com/macos-buildcloud-runners-beta/-/issues/133
My except: external_pull_requests
is not right.
See !1161 (merged) and https://gitlab.com/gitlab-com/macos-buildcloud-runners-beta/-/issues/133