[CI] Address problems with cygwin (#4832)

Author: abravalheri

.github/workflows/main.yml

@@ -182,7 +182,7 @@ jobs:
           packages: >-
             python${{ matrix.python }},
             python${{ matrix.python }}-devel,
-            python${{ matrix.python }}-tox,
+            python${{ matrix.python }}-pip,
             gcc-core,
             git,
       - name: Record the currently selected Python version
@@ -193,11 +193,17 @@ jobs:
         run: |
           python -c 'import platform; print("python-version=" + platform.python_version())' >> ${GITHUB_OUTPUT}
         shell: C:\cygwin\bin\env.exe CYGWIN_NOWINPATH=1 CHERE_INVOKING=1 C:\cygwin\bin\bash.exe -leo pipefail -o igncr {0}
+      - name: Install tox using pip
+        shell: C:\cygwin\bin\env.exe CYGWIN_NOWINPATH=1 CHERE_INVOKING=1 C:\cygwin\bin\bash.exe -leo pipefail -o igncr {0}
+        run: |
+          # Workaround for https://github.com/pypa/setuptools/issues/4831
+          python -m pip install tox
       - name: Run tests
         shell: C:\cygwin\bin\env.exe CYGWIN_NOWINPATH=1 CHERE_INVOKING=1 C:\cygwin\bin\bash.exe -leo pipefail -o igncr {0}
         run: |
-          git config --global --add safe.directory "$(cygpath -u "$GITHUB_WORKSPACE")" # workaround for #3408
-          tox
+          git config --global --add safe.directory "$(cygpath -u "${{ github.workspace }}")" # workaround for #3408
+          echo "$(cygpath -u "${{ github.workspace }}")" # for debugging purposes
+          python -m tox
       - name: Create coverage report
         if: hashFiles('.coverage') != ''  # Rudimentary `file.exists()`
         run: |