Use gui base when building with cx_Freeze

Since cx_Freeze>=7.0, 'Win32GUI' value for base is no more supported.

Closes #14606
(grafted from 8d0759bc0e9a1f3caada64baf51ea67b84e7fca4)

--HG--
branch : 6.0

tryton/setup-freeze.py

@@ -141,7 +141,7 @@ setup(name='tryton',
         },
     executables=[Executable(
             'bin/tryton',
-            base='Win32GUI' if sys.platform == 'win32' else None,
+            base='gui' if sys.platform == 'win32' else None,
             icon=os.path.join(
                 'tryton', 'data', 'pixmaps', 'tryton', 'tryton.ico'),
             )])