Revert "BLD: pin numpy to particular variant that is built for all our deps
xref #17619

This reverts commit 6930f27e78b2b61a4df31b667a816fa53e49ffed.

closes #17620

looks like this now builds correctly (with the reverted pin). though it does downgrade numpy/blas appropriately, so I guess conda-forge fixed the dep issue. cc @jorisvandenbossche @gfyoung  >  it does downgrade numpy/blas appropriately,

Yes, but it only does downgrade the blas version, not numpy version, so that doesn't affect the ABI compatibility of pandas. So indeed the deps issue seems fixed by conda-forge (there should have been some package that lacked numpy 1.13 build forcing it to downgrade)

Thanks for the follow-up!