Unpin msys2 in CI...

Author: oscarbenjamin

.github/workflows/buildwheel.yml

@@ -19,7 +19,7 @@ jobs:
         with:
           python-version: '3.13'
 
-      - uses: msys2/setup-msys2@v2.27.0
+      - uses: msys2/setup-msys2@v2
         with:
           msystem: mingw64
           # path-type inherit is used so that when cibuildwheel calls msys2 to