Remove win32 builds altogether

[eddiebergman]

tldr; Fully dropped building prebuilt binaries for win32 because scipy finally did it too, they said they would a while ago but only fully did it 2 days back.

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So it seems that Scipy updated to 1.9.2 2 days ago (08/10/22) and as part of that, they stopped releasing win32 completely. This meant when building GraKeL, it would download the source of scipy and try to compile it manually.

Ctrl + f for win32 and you'll see they dropped it between the two versions

• Wheels for 1.9.2
• Wheels for 1.9.1

It seems odd they would drop it with a minor release so I went looking at their github.

One issue specifically asks about Python 3.10 which I had disabled previously but one of the maintainers replied in there, saying they would drop win32 wheels from scipy>=1.8. There was however, still win32 wheels available from 1.8.0 -> 1.9.1.

There is also an issue from 2 days ago where they apparently stated they updated their build infrastructure which I guess is where they finally dropped it. Looking at the workflow runs they linked in that issue, there's no build for win32 at all so I guess from this point on it's fully dropped support for pre-built win32 wheels.

So the choices are essentially (in order of recommendation):

• To roll with scipy and just follow their lead on dropping win32 wheels
• To upperbound scipy<=1.9.1
• To somehow install the toolchain needed to get scipy to build on github action servers.
  • If it were simple, scipy would just do it themselves
  • ...How da heck do you compile their underlying FORTRAN?

I went with the first because, well, it's easiest and upperbounding will lead to similar problems in the future, someone want's GraKeL and the newest scikit learn, and they will both have conflicting scipy versions.

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[codecov]

Codecov Report

Merging #85 (a345c30) into master (af0049c) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master      #85   +/-   ##
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  Coverage   69.25%   69.25%           
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  Files          37       37           
  Lines        7059     7059           
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  Hits         4889     4889           
  Misses       2170     2170           

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