Update changelog for v2.2.6
Update changelog for v2.2.6

Change-Id: I53f7d3c52174dad547c0272fc6c24b00d8548c9b

tvoli/shaka-player,vimond/shaka-player,shaka-project/shaka-player,TheModMaker/shaka-player,tvoli/shaka-player,TheModMaker/shaka-player,shaka-project/shaka-player,TheModMaker/shaka-player,TheModMaker/shaka-player,tvoli/shaka-player,shaka-project/shaka-player,tvoli/shaka-player,shaka-project/shaka-player,vimond/shaka-player,vimond/shaka-player