Upgrade python version to fix known memory leaks

- Issue #24469: Fixed memory leak caused by int subclasses without overridden
  tp_free (e.g. C-inherited Cython classes).
- Issue #27330: Fixed possible leaks in the ctypes module.
- Issue #27932: Prevent memory leak in win32_ver().
- Issue #26168: Fixed possible refleaks in failing Py_BuildValue() with the "N"
  format unit.
- Issue #26718: super.__init__ no longer leaks memory if called multiple times.
  NOTE: A direct call of super.__init__ is not endorsed!
- Issue #25745: Fixed leaking a userptr in curses panel destructor.
- Issue #25945: Fixed a crash when unpickle the functools.partial object with
  wrong state.  Fixed a leak in failed functools.partial constructor.
  "args" and "keywords" attributes of functools.partial have now always types
  tuple and dict correspondingly.
- Issue #25725: Fixed a reference leak in cPickle.loads() when unpickling
  invalid data including tuple instructions.
- Issue #25688: Fixed file leak in ElementTree.iterparse() raising an error.
- Issue #27044: Add ConfigDialog.remove_var_callbacks to stop memory leaks.
- Issue #25578: Fix (another) memory leak in SSLSocket.getpeercer().
- Issue #25569: Fix memory leak in SSLSocket.getpeercert().

- Issue #24456: Fixed possible buffer over-read in adpcm2lin() and lin2adpcm()
  functions of the audioop module.  Fixed SystemError when the state is not a
  tuple.  Fixed possible memory leak.
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