multimedia/obs-multi-rtmp: Update distinfo: upstream released new version without changing the version number

Upstream, instead of creating a new tag, remade the existing 0.7.4,
and added the following commits:
https://github.com/sorayuki/obs-multi-rtmp/commit/fcba9cb39bd4b05ea18ed8b54e4355f0cdc59178
https://github.com/sorayuki/obs-multi-rtmp/commit/daf0d3b4578e0eef9c8a36de5b745bccc4b10aba

PR: 294163