golang: Prepare path for libgolang.dll before importing _golang

Else it fails to import on Windows:

    collecting ... 05c8:err:module:import_dll Library libgolang.dll (which is needed by L"Z:\\home\\kirr\\src\\tools\\go\\pygo-win\\pygolang\\golang\\_golang.cp310-win_amd64.pyd") not found
    collected 0 items / 1 error

    =========================================================== ERRORS ===========================================================
    ___________________________________________ ERROR collecting golang/golang_test.py ___________________________________
    ImportError while importing test module 'Z:\home\kirr\src\tools\go\pygo-win\pygolang\golang\golang_test.py'.
    Hint: make sure your test modules/packages have valid Python names.
    Traceback:
    C:\Program Files\Python310\lib\importlib\__init__.py:126: in import_module
        return _bootstrap._gcd_import(name[level:], package, level)
    golang\__init__.py:45: in <module>
        from golang._golang import _pysys_exc_clear as _sys_exc_clear
    E   ImportError: DLL load failed while importing _golang: Модуль не найден.

We need to increase required setuptools_dso version because dylink_prepare_dso
and generation of *_dsoinfo.py modules was done after setuptools_dso 2.

golang/__init__.py

 # -*- coding: utf-8 -*-
-# Copyright (C) 2018-2022  Nexedi SA and Contributors.
+# Copyright (C) 2018-2023  Nexedi SA and Contributors.
 #                          Kirill Smelkov <kirr@nexedi.com>
 #
 # This program is free software: you can Use, Study, Modify and Redistribute
@@ -42,6 +42,9 @@ from golang._gopath import gimport  # make gimport available from golang
 import inspect, sys
 import decorator, six
 
+import setuptools_dso
+setuptools_dso.dylink_prepare_dso('golang.runtime.libgolang')
+
 from golang._golang import _pysys_exc_clear as _sys_exc_clear
 
 # @func is a necessary decorator for functions for selected golang features to work.

pyproject.toml

 [build-system]
-requires = ["setuptools", "wheel", "setuptools_dso >= 1.7", "cython", "gevent"]
+requires = ["setuptools", "wheel", "setuptools_dso >= 2.7", "cython", "gevent"]

setup.py

@@ -152,7 +152,7 @@ class develop(XInstallGPython, _develop):
 # requirements of packages under "golang." namespace
 R = {
     'cmd.pybench':      {'pytest'},
-    'pyx.build':        {'setuptools', 'wheel', 'cython', 'setuptools_dso >= 1.7'},
+    'pyx.build':        {'setuptools', 'wheel', 'cython', 'setuptools_dso >= 2.7'},
     'x.perf.benchlib':  {'numpy'},
 }
 # TODO generate `a.b -> a`, e.g. x.perf = join(x.perf.*); x = join(x.*)
@@ -313,6 +313,8 @@ setup(
     include_package_data = True,
 
     install_requires = ['gevent', 'six', 'decorator', 'Importing;python_version<="2.7"',
+                        # only runtime part: for dylink_prepare_dso
+                        'setuptools_dso >= 2.7',
                         # pyx.build -> setuptools_dso uses multiprocessing
                         # FIXME geventmp fails on python2, but setuptools_dso
                         # uses multiprocessing only on Python3, so for now we