adding entry file to ChangeLog.d for PR3592

Signed-off-by: Daniel Otte <d.otte@wut.de>
diff --git a/ChangeLog.d/adjusting sliding_window_size_PR3592.txt b/ChangeLog.d/adjusting sliding_window_size_PR3592.txt
new file mode 100644
index 0000000..6089565
--- /dev/null
+++ b/ChangeLog.d/adjusting sliding_window_size_PR3592.txt
@@ -0,0 +1,3 @@
+Changes
+   * Reduce stack usage significantly during sliding window exponentiation.
+     Reported in #3591 and fix contributed in #3592 by Daniel Otte.