Pythran not correctly installed for windows installations of SGT

[AlainKadar]

The cpp modules for StructuralGT no longer build for windows. The error is related to pythran not having correctly installed:

Traceback (most recent call last):
  File "D:\a\StructuralGT\StructuralGT\setup.py", line 51, in <module>
    ext_modules=cythonize(
                ~~~~~~~~~^
        [
        ^
    ...<34 lines>...
        ]
        ^
    ),
    ^
  File "C:\Users\runneradmin\micromamba\envs\test\Lib\site-packages\Cython\Build\Dependencies.py", line 978, in cythonize
    ctx = Context.from_options(c_options)
  File "C:\Users\runneradmin\micromamba\envs\test\Lib\site-packages\Cython\Compiler\Main.py", line 95, in from_options
    return cls(options.include_path, options.compiler_directives,
               options.cplus, options.language_level, options=options)
  File "C:\Users\runneradmin\micromamba\envs\test\Lib\site-packages\Cython\Compiler\Main.py", line 72, in __init__
    from . import Builtin, CythonScope
  File "C:\Users\runneradmin\micromamba\envs\test\Lib\site-packages\Cython\Compiler\CythonScope.py", line 3, in <module>
    from .UtilityCode import CythonUtilityCode
  File "C:\Users\runneradmin\micromamba\envs\test\Lib\site-packages\Cython\Compiler\UtilityCode.py", line 2, in <module>
    from .TreeFragment import parse_from_strings, StringParseContext
  File "C:\Users\runneradmin\micromamba\envs\test\Lib\site-packages\Cython\Compiler\TreeFragment.py", line 16, in <module>
    from .Visitor import VisitorTransform
  File "Cython/Compiler/Visitor.py", line 13, in init Cython.Compiler.Visitor
  File "C:\Users\runneradmin\micromamba\envs\test\Lib\site-packages\Cython\Compiler\Nodes.py", line 33, in <module>
    from .Pythran import has_np_pythran, pythran_type, is_pythran_buffer
  File "C:\Users\runneradmin\micromamba\envs\test\Lib\site-packages\Cython\Compiler\Pythran.py", line 7, in <module>
    pythran_is_pre_0_9 = tuple(map(int, pythran.__version__.split('.')[0:2])) < (0, 9)
                                        ^^^^^^^^^^^^^^^^^^^
AttributeError: module 'pythran' has no attribute '__version__'

This error occurs during GitHub actions and is reproduced on other windows machines. The error is resolved when pythran is explicitly installed.

[AlainKadar]

Because pythran is a transitive dependency, it is not explicitly listed in the requirements. But because explicitly installing pythran resolves the error, it has been temporarily added as a requirement in pyproject.toml and the testing environment at github/workflows/conda-envs/env.yml. When the source of this error is found, these requirements can be removed and this issue can be closed.