unbound: update to 1.25.1

unbound: update to 1.25.1

From upstream: 1.25.1 consolidates security fixes for issues
reported over a period of time. There are fixes for CVE-2026-33278,
CVE-2026-42944, CVE-2026-42959, CVE-2026-32792, CVE-2026-40622,
CVE-2026-41292, CVE-2026-42534, CVE-2026-42923, CVE-2026-42960,
CVE-2026-44390 and CVE-2026-44608.

Full details at

https://www.nlnetlabs.nl/news/2026/May/20/unbound-1.25.1-released/

and

https://www.nlnetlabs.nl/news/2026/Apr/29/unbound-1.25.0-released/

Signed-off-by: Tyrel M. McQueen <redacted>