Upgrade of Bitnami install fails from DF2.0.2 to latest

[Symfony\Component\Process\Exception\RuntimeException]
The process has been signaled with signal “5”.

Script php artisan optimize handling the post-install-cmd event returned with an error

[RuntimeException]
Error Output:

I am following the upgrade instructions mentioned here. https://wiki.dreamfactory.com/DreamFactory/Installation#Upgrade