update type of fee rate

Author: liangping

proto/side/btcbridge/tx.proto

@@ -96,7 +96,7 @@ message MsgWithdrawBitcoinRequest {
   // withdraw amount in satoshi, etc: 100000000sat = 1btc
   string amount = 2;
   // fee rate in sats/vB
-  int64 fee_rate = 3;
+  string fee_rate = 3;
 }
 
 // MsgWithdrawBitcoinResponse defines the Msg/WithdrawBitcoin response type.

x/btcbridge/keeper/msg_server.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"context"
 	"encoding/base64"
+	"strconv"
 
 	"github.com/btcsuite/btcd/btcutil/psbt"
 	sdk "github.com/cosmos/cosmos-sdk/types"
@@ -137,7 +138,11 @@ func (m msgServer) WithdrawBitcoin(goCtx context.Context, msg *types.MsgWithdraw
 		return nil, err
 	}
 
-	_, err = m.Keeper.NewSigningRequest(ctx, msg.Sender, coin, msg.FeeRate, "")
+	feeRate, err := strconv.ParseInt(msg.FeeRate, 10, 64)
+	if err != nil {
+		return nil, err
+	}
+	_, err = m.Keeper.NewSigningRequest(ctx, msg.Sender, coin, feeRate, "")
 	if err != nil {
 		return nil, err
 	}

x/btcbridge/types/message_withdraw_bitcoin.go

@@ -1,6 +1,8 @@
 package types
 
 import (
+	"strconv"
+
 	sdkerrors "cosmossdk.io/errors"
 	sdk "github.com/cosmos/cosmos-sdk/types"
 )
@@ -10,7 +12,7 @@ const TypeMsgWithdrawBitcoin = "withdraw_bitcoin"
 func NewMsgWithdrawBitcoinRequest(
 	sender string,
 	amount string,
-	feeRate int64,
+	feeRate string,
 ) *MsgWithdrawBitcoinRequest {
 	return &MsgWithdrawBitcoinRequest{
 		Sender:  sender,
@@ -56,7 +58,12 @@ func (msg *MsgWithdrawBitcoinRequest) ValidateBasic() error {
 		return err
 	}
 
-	if msg.FeeRate <= 0 {
+	feeRate, err := strconv.ParseInt(msg.FeeRate, 10, 64)
+	if err != nil {
+		return err
+	}
+
+	if feeRate <= 0 {
 		return sdkerrors.Wrap(ErrInvalidFeeRate, "fee rate must be greater than zero")
 	}