Update v5_asset_service.go (hirokisan#177)

https://bybit-exchange.github.io/docs/v5/asset/unitransfer

It should be fromMemberId, not fromMemberID (and toMemberId, not toMemberID)

Also, fromAccountType can be equal to toAccountType

e.g you can transfer from one spot subaccount to another spot subaccount

v5_asset_service.go

@@ -150,8 +150,8 @@ type V5CreateUniversalTransferParam struct {
 	Amount          string        `json:"amount"`
 	FromAccountType AccountTypeV5 `json:"fromAccountType"`
 	ToAccountType   AccountTypeV5 `json:"toAccountType"`
-	FromMemberID    int           `json:"fromMemberID"`
-	ToMemberID      int           `json:"toMemberID"`
+	FromMemberID    int           `json:"fromMemberId"`
+	ToMemberID      int           `json:"toMemberId"`
 }
 
 func (p V5CreateUniversalTransferParam) validate() error {
@@ -168,9 +168,6 @@ func (p V5CreateUniversalTransferParam) validate() error {
 	if p.Coin == "" || p.FromAccountType == "" || p.ToAccountType == "" {
 		return fmt.Errorf("coin, fromAccountType and toAccountType needed")
 	}
-	if p.FromAccountType == p.ToAccountType {
-		return fmt.Errorf("toAccountType and fromAccountType must differ")
-	}
 	return nil
 }