BLD: fix submodule update in gitpod.Dockerfile
BLD: fix submodule update in gitpod.Dockerfile

This is analogous to what SciPy does.

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