params: enable constantinople on ropsten at 4.2M

params/config.go

@@ -66,7 +66,7 @@ var (
 		EIP155Block:         big.NewInt(10),
 		EIP158Block:         big.NewInt(10),
 		ByzantiumBlock:      big.NewInt(1700000),
-		ConstantinopleBlock: nil,
+		ConstantinopleBlock: big.NewInt(4200000),
 		Ethash:              new(EthashConfig),
 	}