sysutils/dsblogoutmgr: Update to 1.3.1

A segfault which occured on FreeBSD 13-CURRENT has been fixed.

PR: 236479
Submitted by: Marcel Kaiser <mk@nic-nac-project.org> (maintainer)
Relnotes: https://freeshell.de/~mk/projects/dsblogoutmgr-relnotes.html