Fixed CreateProvider to use POST
Fixed CreateProvider to use POST

jono-90/RiotSharp,BenFradet/RiotSharp,oisindoherty/RiotSharp,JanOuborny/RiotSharp,Challengermode/RiotSharp,aktai0/RiotSharp,Oucema90/RiotSharp,Shidesu/RiotSharp,frederickrogan/RiotSharp,florinciubotariu/RiotSharp