gateio perpetual contract setleverage

[dazi005]

New Issue

I tested the perpetual contract of gateio, and the setleverage method was not implemented

[shazbert]

In the meantime you can hook directly into package level method if needed.

example:

e, ok := exch.(*gateio.Gateio)
if !ok {
    panic("sad")
}

pair := currency.NewPair(currency.BTC, currency.USDT)
pair.Delimiter = "_" // Required formatting

leverage := 100 // lfg
settlement := currency.USDT.Lower().String()

_, err := e.UpdateFuturesPositionLeverage(context.Background(), settlement, pair, leverage, 0 /*this bad boy here is cross leverage limit*/)
if err != nil {
	panic(err.Error())
}