CHANGES: add a commit that will be backported to 4.99. [skip ci]

(cherry picked from commit 2fd3048cbf48fbf358ebb708dc9e949a9e4fbfe3)
diff --git a/CHANGES b/CHANGES
index 2c7d07d..b8a6230 100644
--- a/CHANGES
+++ b/CHANGES
@@ -2,6 +2,8 @@
   Summary for 4.99.4 tcpdump release (so far!)
     Updated printers:
       LSP ping: Fix "Unused value" warnings from Coverity.
+    Building and testing:
+      Require at least autoconf 2.69.
 
 Thursday, January 12, 2023 / The Tcpdump Group
   Summary for 4.99.3 tcpdump release