Issue #15406: Fix deprecation warning in ctypes test_bitfields.py

Patch by Flávio Ribeiro.

diff --cc Misc/ACKS
index d0850636aab8d95296cd703f5fc84b4325e40d0b,95c06baffd18c850bee16e36493c6fbe790e8752..fc08cad25b73a587c8ade36fd31ab4721d05de06
--- 1/Misc/ACKS
--- 2/Misc/ACKS
+++ b/Misc/ACKS
@@@ -865,12 -778,11 +865,13 @@@ Michael P. Reill
  Bernhard Reiter
  Steven Reiz
  Roeland Rengelink
 -Tim Rice
 +Antoine Reversat
+ Flávio Ribeiro
  Francesco Ricciardi
 +Tim Rice
  Jan Pieter Riegel
  Armin Rigo
 +Arc Riley
  Nicholas Riley
  Jean-Claude Rimbault
  Vlad Riscutia