BetweenBidAdapter: default cur is USD (#3977)
BetweenBidAdapter: default cur is USD (#3977)

Co-authored-by: Ignat Khaylov <e6004eb0b5863e45e3e783f5ef9ee2ac49efed51@Ignats-MacBook-Pro.local>
prebid/prebid.github.io,prebid/prebid.github.io,prebid/prebid.github.io