BF: install_requires not just requires for setup() call
BF: install_requires not just requires for setup() call

Originally detected while running DataLad tests on CRON
  https://github.com/datalad/datalad/issues/3395

gitpython-developers/gitpython,gitpython-developers/gitpython,gitpython-developers/GitPython,gitpython-developers/GitPython