root/pypi: links for spack

root/pypi spack-0.5.2.tar.gz
root/pypi spack-0.5.1.tar.gz
root/pypi spack-0.5.tar.gz
root/pypi spack-0.4.tar.gz
root/pypi spack-0.4.linux-x86_64.tar.gz
root/pypi spack-0.3.1.tar.gz