3578 [video_player_platform_interface] Bump version for NNBD stable (cla: yes, nnbd, p: video_player, waiting for tree to go green)

3624 [video_player] Bump app-facing version for NNBD stable (cla: yes, p: video_player)

3668 [video_player] fixed misleading size and aspect ratio documentation (cla: yes, p: video_player, waiting for tree to go green)

3669 [Video_Player] Remove the deprecated API reference. (cla: yes, p: video_player, platform-android, waiting for tree to go green)

3671 [video_player] add http headers (cla: yes, p: video_player, platform-android, platform-ios)

3702 [video_player_platform_interface] add http headers (cla: yes, p: video_player)