Run pip freeze effectively

This doesn't fix the bigger issue, it just addresses something from
the last commit.

Author: EliahKagan

.github/workflows/cygwin-test.yml

@@ -58,7 +58,7 @@ jobs:
     - 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
+        python -m pip install -U pip $(python -m pip freeze --all | grep -ow ^setuptools) wheel
 
     - name: Install project and test dependencies
       run: |