bpo-32592: Set Windows 8 as the minimum required version for API support (GH-15951)

diff --git a/PC/pyconfig.h b/PC/pyconfig.h
index 9304c72..d407e1d 100644
--- a/PC/pyconfig.h
+++ b/PC/pyconfig.h
@@ -135,9 +135,9 @@
 #endif /* MS_WIN64 */
 
 /* set the version macros for the windows headers */
-/* Python 3.5+ requires Windows Vista or greater */
-#define Py_WINVER 0x0600 /* _WIN32_WINNT_VISTA */
-#define Py_NTDDI NTDDI_VISTA
+/* Python 3.9+ requires Windows 8 or greater */
+#define Py_WINVER 0x0602 /* _WIN32_WINNT_WIN8 */
+#define Py_NTDDI NTDDI_WIN8
 
 /* We only set these values when building Python - we don't want to force
    these values on extensions, as that will affect the prototypes and