bpo-37723: Fix performance regression on regular expression parsing. (GH-15030)

Improve performance of sre_parse._uniq function.
diff --git a/Misc/ACKS b/Misc/ACKS
index 9ff74ec..6463b53 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -1708,6 +1708,7 @@
 Hector Urtubia
 Lukas Vacek
 Ville Vainio
+Yann Vaginay
 Andi Vajda
 Case Van Horsen
 John Mark Vandenberg