audio/rsgain: Update to 3.5.1

This is a patch release to fix a critical bug impacting Opus files with
3 or more audio channels. This bug is related to the CRC32 calculation
in the Ogg header and may cause the file to become unplayable. Users
are strongly recommended to upgrade immediately.

Any files that have been impacted by this bug can be repaired by
scanning them again with this version.

https://github.com/complexlogic/rsgain/releases/tag/v3.5.1

MFH: 2024Q2
(cherry picked from commit 5cea2cde7fee503f8d0b60e4d6a91196011047c6)