Account Update
Import the ethers and @kaiachain/ethers-ext packages to add kaia features on ethers.js
Define sender address, sender private key and new private key to be changed
Set up the provider with the specified kairos testnet URL. A provider in ethers is a read-only abstraction to access the blockchain data.
Also, you can change the provider URL from kairos to quicknode
Create a sender's wallet with the private key and provider
Compute the public key from the new private key
Declare a transaction in the key field with the computed public key
Send the tx to the blockchain. Function sendTransaction
internally signs with the private key of the account and then transmits it to the blockchain network.
The wait function returns the tx receipt if it is completed in the blockchain.