TST: Bump the minimun `typing_extensions` version to 3.7.4.2
TST: Bump the minimun `typing_extensions` version to 3.7.4.2

This is the first version that includes `SupportsIndex`

grlee77/numpy,mattip/numpy,pbrod/numpy,mhvk/numpy,pdebuyl/numpy,endolith/numpy,jakirkham/numpy,pbrod/numpy,mhvk/numpy,madphysicist/numpy,madphysicist/numpy,seberg/numpy,jakirkham/numpy,seberg/numpy,grlee77/numpy,grlee77/numpy,endolith/numpy,numpy/numpy,jakirkham/numpy,rgommers/numpy,mattip/numpy,mhvk/numpy,mattip/numpy,madphysicist/numpy,anntzer/numpy,rgommers/numpy,pbrod/numpy,anntzer/numpy,anntzer/numpy,numpy/numpy,simongibbons/numpy,rgommers/numpy,charris/numpy,simongibbons/numpy,mhvk/numpy,madphysicist/numpy,simongibbons/numpy,pbrod/numpy,jakirkham/numpy,numpy/numpy,madphysicist/numpy,seberg/numpy,endolith/numpy,pdebuyl/numpy,charris/numpy,numpy/numpy,mhvk/numpy,simongibbons/numpy,anntzer/numpy,pbrod/numpy,seberg/numpy,pdebuyl/numpy,rgommers/numpy,mattip/numpy,charris/numpy,charris/numpy,pdebuyl/numpy,grlee77/numpy,endolith/numpy,jakirkham/numpy,simongibbons/numpy,grlee77/numpy