Process : Upgrade Magento version from 2.2 to 2.3
As per my client requirement, I tried to upgrade Magento from 2.2 to 2.3 as mentioned in this URL: https://devdocs.magento.com/guides/v2.3/comp-mgr/cli/cli-upgrade.html
All steps were run properly but after run
composer update command it will throw following Fatal error after some time as per mention into the screenshot.
And then after exit from
composer update command.
Please suggest me how can I fix this error ?.
Thanks in advance.