The bonus payment is taxed on a receipts basis. If the bonus payment was received by you in May 2021, then is taxable in the 2021 to 2022 tax year.
You left the UK in November 2020, which is the 2020 to 2021 tax year. Your residence status for 2021 to 2022 will determine if this is taxable or not for that year. You can refer to the further guidance here:
Tax on your UK income if you live abroad