Remove last from __future__ imports

[eerovaher]

The removed imports had no effect in Python 3.

It can be verified that no __future__ imports remain by running

$ git grep __future__

[codecov]

Codecov Report

Merging #2432 (7c01848) into main (eeb0d07) will decrease coverage by 0.00%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #2432      +/-   ##
==========================================
- Coverage   62.93%   62.92%   -0.01%     
==========================================
  Files         133      133              
  Lines       17273    17269       -4     
==========================================
- Hits        10870    10866       -4     
  Misses       6403     6403              

Impacted Files	Coverage Δ
...oplanet_orbit_database/exoplanet_orbit_database.py	93.02% <ø> (-0.16%)	⬇️
astroquery/query.py	58.54% <ø> (-0.18%)	⬇️
astroquery/sdss/core.py	85.91% <ø> (-0.05%)	⬇️
astroquery/sdss/field_names.py	92.68% <ø> (-0.18%)	⬇️

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[bsipocz]

Thanks, @eerovaher.