ENH: add pyproject.toml

[mathurinm]

should fix #122

[codecov-commenter]

Codecov Report

Merging #217 (569c1e5) into main (f7fa260) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #217   +/-   ##
=======================================
  Coverage   85.79%   85.79%           
=======================================
  Files          14       14           
  Lines         929      929           
  Branches      128      128           
=======================================
  Hits          797      797           
  Misses        101      101           
  Partials       31       31           

Flag	Coverage Δ
unittests	∅ <ø> (∅)

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[mathurinm]

did better in #218 in parallel (only scipy is needed as a requirement at build time, for access to blas)