audio/libmysofa: Update to 1.3.1
No functional changes. Previously included build fixes were
just released under a new tag.
Add STATIC option to toggle the static library build. Enabled by
default as before. Addresses wanting to disable static library in [1].
https://github.com/hoene/libmysofa/releases/tag/v1.3.1
PR: 266856 [1]
Reported by: diizzy [1]