Fix Windows CI

For some reason, the (virtual) package
mingw-w64-x86_64-python3-setuptools doesn't exist anymore
(https://packages.msys2.org/packages/mingw-w64-x86_64-python3-setuptools
is empty), but mingw-w64-x86_64-python3-setuptools does exist (and was
earlier providing the actual package for the former).

ci/win_install_deps.cmd

@@ -64,7 +64,7 @@ mingw-w64-x86_64-ninja ^
 mingw-w64-x86_64-ncurses ^
 mingw-w64-x86_64-readline ^
 mingw-w64-x86_64-python3 ^
-mingw-w64-x86_64-python3-setuptools ^
+mingw-w64-x86_64-python-setuptools ^
 mingw-w64-x86_64-python3-packaging ^
 mingw-w64-x86_64-python3-pip ^
 mingw64/mingw-w64-x86_64-dlfcn ^