FYI: Darwin CI currently broken for forks

[Matthew Pickering]

Hi all,

There is a configuration issue with the darwin builders which has
meant that for the last 6 days CI has been broken if you have pushed
from a fork because the majority of darwin builders are only
configured to work with branches pushed to the main project. These
failures manifest as timeout errors
(https://gitlab.haskell.org/blamario/ghc/-/jobs/733244).

Hopefully this can be resolved in the coming days.

Cheers,

Matt