Cloud build not supported (yet) with 2019.3?

I'm seeing a packagemanager related failure for mac/windows/linux builds at the same point every time:



Googling around, the only thread I see about this suggested downgrading back to 2019.1:

https://answers.unity.com/questions/1639774/package-manager-errors-in-cloud-build-in-2019.html

Is that accurate? If so, when will I be able to use cloud build with my upgraded-to-2019.3x projects?

Thanks!

-S