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

Patch by Flávio Ribeiro.
diff --git a/Misc/ACKS b/Misc/ACKS
index 16847be..95c06ba 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -778,6 +778,7 @@
 Bernhard Reiter
 Steven Reiz
 Roeland Rengelink
+Flávio Ribeiro
 Tim Rice
 Francesco Ricciardi
 Jan Pieter Riegel