Revert "Pin to Python 3.9.16-1"

This reverts commit 139320b.

Author: radarhere

.github/workflows/test-cygwin.yml

@@ -50,7 +50,7 @@ jobs:
         uses: actions/checkout@v4
 
       - name: Install Cygwin
-        uses: egor-tensin/setup-cygwin@v4
+        uses: cygwin/cygwin-install-action@v4
         with:
           packages: >
             gcc-g++
@@ -71,7 +71,6 @@ jobs:
             make
             netpbm
             perl
-            python39=3.9.16-1
             python3${{ matrix.python-minor-version }}-cffi
             python3${{ matrix.python-minor-version }}-cython
             python3${{ matrix.python-minor-version }}-devel
@@ -89,7 +88,7 @@ jobs:
 
       - name: Select Python version
         run: |
-          ln -sf c:/tools/cygwin/bin/python3.${{ matrix.python-minor-version }} c:/tools/cygwin/bin/python3
+          ln -sf c:/cygwin/bin/python3.${{ matrix.python-minor-version }} c:/cygwin/bin/python3
 
       - name: Get latest NumPy version
         id: latest-numpy