Readme: explain ci

[avaer]

The readme currently does not explain how the ci works.

I couldn’t find the source for the node 12 ci line for example. It would be useful to also know how the v8 lkgr is brought in, and what the current version of that is.

The broader question to clarify would be how exactly node and v8 lkgr come together, and result in the ci builds.

[ryzokuken]

Hi @modulesio!

You're very right. That said, could you also make me understand why it is important to document all these publicly? A lot of these things don't bring a lot of value to the community when disclosed in my opinion (particularly because hardly anyone cares) and definitely increases the overhead in maintaining this fork.