add default_for_currency to request body
add default_for_currency to request body

dominicphillips/stripe-go,ChannelMeter/stripe-go,ChannelMeter/stripe-go,mondough/stripe-go,froatsnook/stripe-go,dominicphillips/stripe-go,stripe/stripe-go,mondough/stripe-go,stripe/stripe-go,froatsnook/stripe-go