Fix 2.12.1 release note
Fix 2.12.1 release note

PiperOrigin-RevId: 342512836

androidx/media,androidx/media,androidx/media,google/ExoPlayer,amzn/exoplayer-amazon-port,ened/ExoPlayer,ened/ExoPlayer,google/ExoPlayer,google/ExoPlayer,amzn/exoplayer-amazon-port,ened/ExoPlayer,amzn/exoplayer-amazon-port