Apply suggestions from code review

Author: aalavandhan

package.json

@@ -39,7 +39,6 @@
     "bignumber.js": "^9.0.0",
     "chai": "^4.2.0",
     "ethereum-waffle": "^3.2.1",
-    "ethereumjs-util": "^7.0.7",
     "ethers": "5.0.18",
     "hardhat": "^2.0.6",
     "pre-commit": "^1.2.2",

test/utils/signatures.ts

@@ -6,7 +6,6 @@ import {
   solidityPack,
   splitSignature,
 } from 'ethers/lib/utils'
-import { ecsign } from 'ethereumjs-util'
 import { BigNumberish, Wallet } from 'ethers'
 
 export const EIP712_DOMAIN_TYPEHASH = keccak256(