net/rsync: update 3.4.2 -> 3.4.3

Changelog: https://download.samba.org/pub/rsync/NEWS#3.4.3

In addition to the six CVE fixes, this release adds defence-in-depth
hardening on several adjacent paths.

Other changes:

• Fixed a regression introduced by the 3.4.0 secure_relative_open() CVE fix
• secure_relative_open() now uses openat2(O_RESOLVE_BENEATH) on FreeBSD 13+

Security: CVE-2026-29518
Security: CVE-2026-43617
Security: CVE-2026-43618
Security: CVE-2026-43619
Security: CVE-2026-43620
Security: CVE-2026-45232
(cherry picked from commit f4f3b3e9632f321d690ba950e9baa79dabad7275)