Try not using a venv for Cygwin on CI

Author: EliahKagan

.github/workflows/cygwin-test.yml

@@ -30,7 +30,7 @@ jobs:
     - name: Install Cygwin
       uses: cygwin/cygwin-install-action@v5
       with:
-        packages: python39 python39-pip python39-virtualenv git wget
+        packages: python39 python39-pip python39-setuptools python39-wheel python39-virtualenv git wget
         add-to-path: false  # No need to change $PATH outside the Cygwin environment.
 
     - name: Arrange for verbose output
@@ -56,20 +56,6 @@ jobs:
         # and cause subsequent tests to fail
         cat test/fixtures/.gitconfig >> ~/.gitconfig
 
-    - name: Set up virtualenv
-      run: |
-        python3.9 -m venv --without-pip .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: |
-        # Get the latest pip, wheel, and prior to Python 3.12, setuptools.
-        python -m pip install -U pip $(pip freeze --all | grep -ow ^setuptools) wheel
-
     - name: Install project and test dependencies
       run: |
         pip install ".[test]"