fix commitments slot

Signed-off-by: Jun Kimura <[email protected]>

module/prover.go

@@ -19,6 +19,9 @@ import (
 	"github.com/hyperledger-labs/yui-relayer/core"
 )
 
+// keccak256(abi.encode(uint256(keccak256("ibc.commitment")) - 1)) & ~bytes32(uint256(0xff))
+var IBCCommitmentsSlot = common.HexToHash("1ee222554989dda120e26ecacf756fe1235cd8d726706b57517715dde4f0c900")
+
 type Prover struct {
 	chain  *ethereum.Chain
 	config ProverConfig
@@ -144,7 +147,7 @@ func (pr *Prover) buildStateProof(path []byte, height int64) ([]byte, error) {
 	// calculate slot for commitment
 	slot := crypto.Keccak256Hash(append(
 		crypto.Keccak256Hash(path).Bytes(),
-		common.Hash{}.Bytes()...,
+		IBCCommitmentsSlot.Bytes()...,
 	))
 	marshaledSlot, err := slot.MarshalText()
 	if err != nil {