Add zod to the benchmark

[rattrayalex]

zod is a json-schema validator designed for TypeScript that is quickly gaining popularity, recently crossing 3m downloads/wk.

I'm curious how it compares to ajv and others

Could it be added to the benchmark?

I notice contributing docs; it looks like all you have to do is add it to this file? https://github.com/ebdrup/json-schema-benchmark/blob/master/validators.js

If so, someone on my team can probably submit a PR.