Update changelog for v2.0.3
Update changelog for v2.0.3

Change-Id: I9704b9eae2bd557fb93180b76d21fe406cb8a7cb

tvoli/shaka-player,tvoli/shaka-player,brightcove/shaka-player,shaka-project/shaka-player,TheModMaker/shaka-player,Ross-cz/shaka-player,shaka-project/shaka-player,russitto/shaka-player,tvoli/shaka-player,tvoli/shaka-player,indiereign/shaka-player,vimond/shaka-player,russitto/shaka-player,TobbeEdgeware/shaka-player,Ross-cz/shaka-player,brightcove/shaka-player,vimond/shaka-player,brightcove/shaka-player,TobbeEdgeware/shaka-player,TheModMaker/shaka-player,shaka-project/shaka-player,indiereign/shaka-player,TheModMaker/shaka-player,Ross-cz/shaka-player,shaka-project/shaka-player,TobbeEdgeware/shaka-player,indiereign/shaka-player,vimond/shaka-player,russitto/shaka-player,TheModMaker/shaka-player