make sure CI stays on VS2019 unless changed explicitly
make sure CI stays on VS2019 unless changed explicitly

pdebuyl/numpy,mhvk/numpy,jakirkham/numpy,seberg/numpy,mhvk/numpy,numpy/numpy,anntzer/numpy,numpy/numpy,rgommers/numpy,mhvk/numpy,pdebuyl/numpy,numpy/numpy,charris/numpy,pdebuyl/numpy,mattip/numpy,mattip/numpy,jakirkham/numpy,charris/numpy,seberg/numpy,jakirkham/numpy,pdebuyl/numpy,mattip/numpy,seberg/numpy,rgommers/numpy,mhvk/numpy,rgommers/numpy,charris/numpy,jakirkham/numpy,mattip/numpy,jakirkham/numpy,numpy/numpy,anntzer/numpy,anntzer/numpy,rgommers/numpy,seberg/numpy,charris/numpy,mhvk/numpy,anntzer/numpy,endolith/numpy,endolith/numpy,endolith/numpy,endolith/numpy