Update play-json to 2.6.6 (#7859)
Update play-json to 2.6.6 (#7859)

Adds some fixes to the configuration mechanism
zaneli/playframework,playframework/playframework,Shenker93/playframework,rajeshpg/playframework,wegtam/playframework,mkurz/playframework,playframework/playframework,rajeshpg/playframework,Shenker93/playframework,mkurz/playframework,wegtam/playframework,benmccann/playframework,wegtam/playframework,Shenker93/playframework,rajeshpg/playframework,zaneli/playframework,marcospereira/playframework,zaneli/playframework,benmccann/playframework,benmccann/playframework,marcospereira/playframework,wegtam/playframework,mkurz/playframework,playframework/playframework,mkurz/playframework,marcospereira/playframework,rajeshpg/playframework,Shenker93/playframework,benmccann/playframework,zaneli/playframework,marcospereira/playframework