Fix instance of ToJSON for ZonedTime
Fix instance of ToJSON for ZonedTime

nurpax/aeson,sol/aeson,23Skidoo/aeson,JPMoresmau/aeson,plaprade/aeson,jkarni/aeson,neobrain/aeson,lykahb/aeson,timmytofu/aeson,sol/aeson,beni55/aeson,neobrain/aeson,abbradar/aeson,roelvandijk/aeson,aelve/json-x,roelvandijk/aeson,SeanRBurton/aeson,dmjio/aeson,sol/aeson,bwo/aeson