Vagrant upgrade to ubuntu 20.04 incoming

[Syzygy]

Anyone using the Vagrantfile to build? I'm upgrading it to ubuntu 20.04 (focal64).

It builds a lot faster if you raise the CPU count and memory.

Might want to check this out and see if it works for you.

https://github.com/polserver/polserver/pull/236

[Yukiko]

At one time, when I was posting releases of the Core on the forums, I tried using Vagrant to setup a Linux VM so I could post Linux releases too. Unfortunately, I wasn't successful. Maybe your update to Vagrant's configuration fixed whatever problems I was encountering back then.

Thanks for all the work you have done with the compiler.