Use Gitlab-CI cache to keep ccache data
as suggested in https://cern.service-now.com/service-portal/view-request.do?n=RQF1289935
This method works much better than the artifacts trick we were using.
as suggested in https://cern.service-now.com/service-portal/view-request.do?n=RQF1289935
This method works much better than the artifacts trick we were using.