Update release notes to reflect builder -> factory change
Update release notes to reflect builder -> factory change

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=178866131

tntcrowd/ExoPlayer,MaTriXy/ExoPlayer,kiall/ExoPlayer,MaTriXy/ExoPlayer,saki4510t/ExoPlayer,tntcrowd/ExoPlayer,androidx/media,superbderrick/ExoPlayer,saki4510t/ExoPlayer,KiminRyu/ExoPlayer,superbderrick/ExoPlayer,ebr11/ExoPlayer,saki4510t/ExoPlayer,google/ExoPlayer,stari4ek/ExoPlayer,kiall/ExoPlayer,amzn/exoplayer-amazon-port,MaTriXy/ExoPlayer,ened/ExoPlayer,tntcrowd/ExoPlayer,ened/ExoPlayer,google/ExoPlayer,superbderrick/ExoPlayer,amzn/exoplayer-amazon-port,stari4ek/ExoPlayer,ebr11/ExoPlayer,ebr11/ExoPlayer,kiall/ExoPlayer,stari4ek/ExoPlayer,androidx/media,KiminRyu/ExoPlayer,ened/ExoPlayer,KiminRyu/ExoPlayer,google/ExoPlayer,amzn/exoplayer-amazon-port,androidx/media