Add SuggestGasTipCap to test client implementation

SuggestGasTipCap was added to ethereum client in ethereum/go-ethereum@7a7abe3
We need to include it in client interface implementation we use in
tests.

pkg/chain/ethereum/ethutil/rate_limiter.go

@@ -3,11 +3,12 @@ package ethutil
 import (
 	"context"
 	"fmt"
+	"math/big"
+
 	"github.com/ethereum/go-ethereum"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/keep-network/keep-common/pkg/rate"
-	"math/big"
 )
 
 type rateLimiter struct {
@@ -96,6 +97,18 @@ func (rl *rateLimiter) SuggestGasPrice(
 	return rl.EthereumClient.SuggestGasPrice(ctx)
 }
 
+func (rl *rateLimiter) SuggestGasTipCap(
+	ctx context.Context,
+) (*big.Int, error) {
+	err := rl.Limiter.AcquirePermit()
+	if err != nil {
+		return nil, fmt.Errorf("cannot acquire rate limiter permit: [%v]", err)
+	}
+	defer rl.Limiter.ReleasePermit()
+
+	return rl.EthereumClient.SuggestGasTipCap(ctx)
+}
+
 func (rl *rateLimiter) EstimateGas(
 	ctx context.Context,
 	call ethereum.CallMsg,

pkg/chain/ethereum/ethutil/rate_limiter_test.go

@@ -2,15 +2,16 @@ package ethutil
 
 import (
 	"context"
-	"github.com/ethereum/go-ethereum"
-	"github.com/ethereum/go-ethereum/common"
-	"github.com/ethereum/go-ethereum/core/types"
-	"github.com/keep-network/keep-common/pkg/rate"
 	"math/big"
 	"strings"
 	"sync"
 	"testing"
 	"time"
+
+	"github.com/ethereum/go-ethereum"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/keep-network/keep-common/pkg/rate"
 )
 
 func TestRateLimiter(t *testing.T) {
@@ -365,6 +366,13 @@ func (mec *mockEthereumClient) SuggestGasPrice(
 	return nil, nil
 }
 
+func (mec *mockEthereumClient) SuggestGasTipCap(
+	ctx context.Context,
+) (*big.Int, error) {
+	mec.mockRequest()
+	return nil, nil
+}
+
 func (mec *mockEthereumClient) EstimateGas(
 	ctx context.Context,
 	call ethereum.CallMsg,
@@ -530,6 +538,14 @@ func getTests(
 				return err
 			},
 		},
+		"test SuggestGasTipCap": {
+			function: func() error {
+				_, err := client.SuggestGasTipCap(
+					context.Background(),
+				)
+				return err
+			},
+		},
 		"test EstimateGas": {
 			function: func() error {
 				_, err := client.EstimateGas(