Workflows do not use any artifacts in their later steps

[seanmakesgames]

https://docs.github.com/en/actions/using-workflows/storing-workflow-data-as-artifacts

Dev cycle times and workflow completion time would benefit from reusing built v8 binaries between workflow steps.

discovered during #37

[lloeki]

I've added some ccache support for local development (OOTB if you use make -f Makefile.docker), otherwise just install ccache and it'll pick it up), I'm planning to add that to CI as well (AFAIK GHA cache size limit is now 10GB)

This should help a lot with builds (and re-builds).