Add Mock.assert_called()

Issue #26323: Add assert_called() and assert_called_once() methods to
unittest.mock.Mock.
diff --git a/Misc/ACKS b/Misc/ACKS
index 0a67f39..a19e113 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -1267,6 +1267,7 @@
 Constantina S.
 Patrick Sabin
 Sébastien Sablé
+Amit Saha
 Suman Saha
 Hajime Saitou
 George Sakkis