Fix _PyObject_FastCall for Python 3.13

[cdce8p]

_PyObject_FastCall will be removed in 3.13. It can safely replaced by PyObject_Vectorcall (available since 3.9) / _PyObject_Vectorcall (available since 3.8). python/cpython#106023 (comment)

https://peps.python.org/pep-0590/

Fixes

  /home/runner/work/mypy/mypy/mypyc/lib-rt/pythonsupport.h: In function ‘update_bases’: (diff)
  /home/runner/work/mypy/mypy/mypyc/lib-rt/pythonsupport.h:62:20: error: implicit declaration of function ‘_PyObject_FastCall’; did you mean ‘PyObject_Call’? [-Werror=implicit-function-declaration] (diff)
     62 |         new_base = _PyObject_FastCall(meth, stack, 1); (diff)
  /home/runner/work/mypy/mypy/mypyc/lib-rt/pythonsupport.h:62:18: error: assignment to ‘PyObject *’ {aka ‘struct _object *’} from ‘int’ makes pointer from integer without a cast [-Werror=int-conversion] (diff)
     62 |         new_base = _PyObject_FastCall(meth, stack, 1); (diff)
        |                  ^ (diff)
  /home/runner/work/mypy/mypy/mypyc/lib-rt/pythonsupport.h: In function ‘init_subclass’: (diff)
  /home/runner/work/mypy/mypy/mypyc/lib-rt/pythonsupport.h:111:11: error: assignment to ‘PyObject *’ {aka ‘struct _object *’} from ‘int’ makes pointer from integer without a cast [-Werror=int-conversion] (diff)
    111 |     super = _PyObject_FastCall((PyObject *)&PySuper_Type, args, 2); (diff)
        |           ^ (diff)