Remove version constraint of setuptools

[nzw0301]

Motivation

setuptools 60.5.0 has been released, https://github.com/pypa/setuptools/releases/tag/v60.5.0.

Description of the changes

Undo the version constraints introduced by #3207

[codecov-commenter]

Codecov Report

Merging #3231 (4cbb391) into master (acdf4b7) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #3231   +/-   ##
=======================================
  Coverage   91.51%   91.51%           
=======================================
  Files         146      146           
  Lines       12011    12011           
=======================================
  Hits        10992    10992           
  Misses       1019     1019           

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update acdf4b7...4cbb391. Read the comment docs.

[hvy]

Nice. Curious but do you know in what sense the previous failure was fixed with this recent release? I first though that we'd have to wait for mpi4py.

[nzw0301]

The previous failure was due to undefined get_versions in setuptools for cygwin, mpi4py/mpi4py#157. New setutools restores get_versions attrubute by this PR. pypa/setuptools#2969 (comment) might be a relevant comment.

[toshihikoyanase]

@HideakiImamura Could you review this PR? This PR will revert the change of your PR #3207.

[hvy]

Thanks for the references. So it was addressed by setuptools as well, meaning it'll also work with older versions of mpi4py and not just the upcoming one with the fix. LGTM!

[HideakiImamura]

LGTM!