fix vendor folder

vendor/github.com/muun/libwallet/V4.go

@@ -0,0 +1,71 @@
+package libwallet
+
+import (
+	"crypto/sha256"
+
+	"github.com/btcsuite/btcutil"
+
+	"github.com/pkg/errors"
+
+	"github.com/btcsuite/btcd/wire"
+)
+
+func CreateAddressV4(userKey, muunKey *HDPublicKey) (MuunAddress, error) {
+
+	witnessScript, err := createWitnessScriptV4(userKey, muunKey)
+	if err != nil {
+		return nil, errors.Wrapf(err, "failed to generate witness script v4")
+	}
+	witnessScript256 := sha256.Sum256(witnessScript)
+
+	address, err := btcutil.NewAddressWitnessScriptHash(witnessScript256[:], userKey.Network.network)
+	if err != nil {
+		return nil, err
+	}
+
+	return &muunAddress{
+		address:        address.EncodeAddress(),
+		version:        addressV4,
+		derivationPath: userKey.Path,
+	}, nil
+}
+
+func createWitnessScriptV4(userKey, muunKey *HDPublicKey) ([]byte, error) {
+	// createRedeemScriptV2 creates a valid script for V2, V3 and V4 schemes
+	return createRedeemScriptV2(userKey, muunKey)
+}
+
+func addUserSignatureInputV4(input Input, index int, tx *wire.MsgTx, privateKey *HDPrivateKey, muunKey *HDPublicKey) (*wire.TxIn, error) {
+
+	if len(input.MuunSignature()) == 0 {
+		return nil, errors.Errorf("muun signature must be present")
+	}
+
+	witnessScript, err := createWitnessScriptV4(privateKey.PublicKey(), muunKey)
+	if err != nil {
+		return nil, err
+	}
+
+	sig, err := signInputV4(input, index, tx, privateKey.PublicKey(), muunKey, privateKey)
+	if err != nil {
+		return nil, err
+	}
+
+	zeroByteArray := []byte{}
+
+	txInput := tx.TxIn[index]
+	txInput.Witness = wire.TxWitness{zeroByteArray, sig, input.MuunSignature(), witnessScript}
+
+	return txInput, nil
+}
+
+func signInputV4(input Input, index int, tx *wire.MsgTx, userKey *HDPublicKey, muunKey *HDPublicKey,
+	signingKey *HDPrivateKey) ([]byte, error) {
+
+	witnessScript, err := createWitnessScriptV4(userKey, muunKey)
+	if err != nil {
+		return nil, err
+	}
+
+	return signNativeSegwitInput(input, index, tx, signingKey, witnessScript)
+}