Account Update
Import the web3 and @kaiachain/web3js-ext packages to add kaia features on web3
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 web3 is a read-only abstraction to access the blockchain data.
Also, you can change the provider URL from kairos to quicknode
Create a KlaytnWeb3 instance using the provider
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.
Signing the transaction with the sender's private key
Send the signed tx to the blockchain. It will return the receipt of the transaction