update changelog.
fixes
$Id: Changelog.txt,v 1.489 2022/06/01 23:21:11 nanard Exp $
+2022/08/06:
+ Fixes DeletePCPMap() for "IPv6 pinholes" with netfilter_nftables backend
+
2022/06/02:
Fixes "Port Triggering" with OpenBSD 4.7+
