CI: pin OpenBLAS to specific build in macOS job to avoid gges issue
CI: pin OpenBLAS to specific build in macOS job to avoid gges issue

xref gh-16949. This doesn't fix the root cause of the problem,
but stops the CI job from failing.

[skip azp] [skip circle]

scipy/scipy,andyfaff/scipy,WarrenWeckesser/scipy,scipy/scipy,mdhaber/scipy,endolith/scipy,ilayn/scipy,anntzer/scipy,WarrenWeckesser/scipy,endolith/scipy,anntzer/scipy,Stefan-Endres/scipy,ilayn/scipy,mdhaber/scipy,Stefan-Endres/scipy,anntzer/scipy,anntzer/scipy,WarrenWeckesser/scipy,WarrenWeckesser/scipy,ilayn/scipy,Stefan-Endres/scipy,mdhaber/scipy,mdhaber/scipy,mdhaber/scipy,scipy/scipy,endolith/scipy,ilayn/scipy,andyfaff/scipy,WarrenWeckesser/scipy,endolith/scipy,anntzer/scipy,endolith/scipy,WarrenWeckesser/scipy,ilayn/scipy,scipy/scipy,andyfaff/scipy,Stefan-Endres/scipy,andyfaff/scipy,Stefan-Endres/scipy,ilayn/scipy,andyfaff/scipy,anntzer/scipy,mdhaber/scipy,endolith/scipy,scipy/scipy,andyfaff/scipy,Stefan-Endres/scipy,scipy/scipy