message: chg: update example script
diff: -const bn = require('bn.js')
  const utils = require('./utils')
  +// it is not recommended to hard-code private keys in the script, this is only for testing.
  const privateKey1 = '0x..'
  const privateKey2 = '0x..'
  async function init() {
  const { matic, wallet } = await utils.getMaticClient('testnet', 'v3')
  - const token1 = '0x..' // address of token to sell
  - const value1 = '' // amount/token id of token 1 to sell
  + const token1 = '0x683E640bb210355B877eae20ae083971eF3BFDbD' // address of token to sell. Provided is a sample erc20 token deployed on testnetv3, with a public `mint` function - for testing
  + const value1 = '1' // amount/token id of token 1 to sell. Please make sure the account holds the specified value
  matic.setWallet(privateKey1) // owner of token1 (order creator)
  - const token2 = '0x.. ' // address of token to buy
  - const value2 = '' // amount/token id of token 2 to sell
  + const token2 = '0x37fc65a422fdCc3BBC8Fa27f32035Bea9aCCA438' // address of token to buy. Provided is a sample erc721 token deployed on testnetv3, with a public `mint` function - for testing. Please make sure the token is not already minted before minting a new token
  + const value2 = '12' // amount/token id of token 2 to sell.
  matic.setWallet(privateKey2) // transaction executor; token owner approves this account to execute the transfer
  const tokenOwner = wallet[0].address
  const spender = wallet[1].address // tx executor
  - const orderFiller = '0x..' // address of account to transfer tokens to
  + const orderFiller = '0x..' // address of account to transfer tokens to. Address corresponding to privateKey2
  - const orderId = '' // order Id is supposed to be unique for each order; 32 byte Hex string
  + const orderId = '' // order Id is supposed to be unique for each order; a random 32 byte Hex string
  const expire = 0 // block number to expire the tx at; 0 for no expiry
  // sell order
  @@ -38,6 +38,7 @@ async function init() {
  token: token2,
  amount: value2,
  }
  +
  const sig = await matic.getTransferSignature(toSell, toBuy, {
  from: tokenOwner,
  })
  