Use `serialization` option for child process communication

[sindresorhus]

childProcess.fork received a new option called serialization, which would let us use the V8 clone algorithm for passing messages instead of JSON. We could then pass types like Buffer.

It was added in Node.js 13.2.0, so we cannot use this until we target Node.js 14.

https://nodejs.org/en/blog/release/v13.2.0/
https://nodejs.org/api/child_process.html#child_process_child_process_fork_modulepath_args_options

[novemberborn]

It's available in Node.js 12.16 now. There's a commit in #2478 which achieves this.

[novemberborn]

FWIW this requires nodejs/node#34797 which I think may have been introduced in 16.4.2, but has not been backported to 14 or 12.

[novemberborn]

Done in #3184.