CI: mac jobs time out

Hi @rbianchi, I've noticed that on recent MR-s the mac pipelines were either marked as failed or were waiting their turn to start (which never happened). I canceled all such pending pipelines manually and then restarted one of them. It stopped adding new lines to the log after printing:

Using wget
Upgrading qt5

and eventually timed out:

ERROR: Job failed: execution took longer than 30m0s seconds

Any ideas about what's going on with our mac jobs? Thanks.