Use *-wheel packages as a better fix for gitpython-developers#2004

This installs the `python-pip-wheel`, `python-setuptools-wheel`,
and `python-wheel-wheel` packages on Cygwini CI, which provide
`.whl` files for `pip`, `setuptools`, and `wheel`.

By making those wheels available, this fixes gitpython-developers#2004 better than the
previous workaround, allowing `ensurepip` to run without the error:

    Traceback (most recent call last):
      File "/usr/lib/python3.9/runpy.py", line 188, in _run_module_as_main
        mod_name, mod_spec, code = _get_module_details(mod_name, _Error)
      File "/usr/lib/python3.9/runpy.py", line 147, in _get_module_details
        return _get_module_details(pkg_main_name, error)
      File "/usr/lib/python3.9/runpy.py", line 111, in _get_module_details
        __import__(pkg_name)
      File "/usr/lib/python3.9/ensurepip/__init__.py", line [30](https://github.com/EliahKagan/GitPython/actions/runs/13454947366/job/37596811693#step:10:31), in <module>
        _SETUPTOOLS_VERSION = _get_most_recent_wheel_version("setuptools")
      File "/usr/lib/python3.9/ensurepip/__init__.py", line 27, in _get_most_recent_wheel_version
        return str(max(_wheels[pkg], key=distutils.version.LooseVersion))
    ValueError: max() arg is an empty sequence

This change takes the place of the main changes in gitpython-developers#2007 and gitpython-developers#2009.
In particular, it should allow `test_installation` to pass again.

This also delists non-wheel Cygwin packages such as `python39-pip`,
which are not needed (or at least no longer needed).

Author: EliahKagan

.github/workflows/cygwin-test.yml

@@ -41,7 +41,7 @@ jobs:
     - name: Install Cygwin
       uses: cygwin/cygwin-install-action@v5
       with:
-        packages: python39 python39-pip python39-virtualenv git wget
+        packages: git python39 python39-pip-wheel python39-setuptools-wheel python39-wheel-wheel
         add-to-path: false  # No need to change $PATH outside the Cygwin environment.
 
     - name: Arrange for verbose output
@@ -69,13 +69,9 @@ jobs:
 
     - name: Set up virtual environment
       run: |
-        python3.9 -m venv --without-pip .venv
+        python3.9 -m venv .venv
         echo 'BASH_ENV=.venv/bin/activate' >>"$GITHUB_ENV"
 
-    - name: Bootstrap pip in virtualenv
-      run: |
-        wget -qO- https://bootstrap.pypa.io/get-pip.py | python
-
     - name: Update PyPA packages
       run: |
         python -m pip install -U pip 'setuptools; python_version<"3.12"' wheel

test/test_installation.py

@@ -4,19 +4,11 @@
 import ast
 import os
 import subprocess
-import sys
-
-import pytest
 
 from test.lib import TestBase, VirtualEnvironment, with_rw_directory
 
 
 class TestInstallation(TestBase):
-    @pytest.mark.xfail(
-        sys.platform == "cygwin" and "CI" in os.environ,
-        reason="Trouble with pip on Cygwin CI, see issue #2004",
-        raises=subprocess.CalledProcessError,
-    )
     @with_rw_directory
     def test_installation(self, rw_dir):
         venv = self._set_up_venv(rw_dir)