allow to pull superschema with `hive:fetch` based on schema checks

This is a suggestion to augment `hive:fetch` command, or possibly introduce an alternative way to pull in superschema which contains changes to subschema which has not been published yet. It is a little bit similar to [this](https://github.com/kamilkisiela/graphql-hive/issues/2750) but my use-case is not for local development but for CI automation.

In some cases, I'd like to construct superschema on a PR branch, take the superschema and run it through Relay compiler in our front-end codebase to be absolutely sure we won't break anything. (FYI we had issue where we approved changes to subschema which renamed `enum` members, it seemed to be ok but then it failed during runtime because of FE usage).

Allowing to run `hive:fetch` with commit SHA that maps to a version in schema checks would solve my problem.