net-p2p/renterd: update to 2.7.1

This update is mandatory to continue participating in the network,
previous versions will cease to work in December 2025!

Changelog: https://github.com/SiaFoundation/renterd/releases/tag/v2.7.1

PR: 291057
MFH: 2025Q4
(cherry picked from commit 790a4934ee403bf87db70f719fb7de2da651f942)