Add `require 'digest/sha2'` for fingerprint
Add `require 'digest/sha2'` for fingerprint

It raises a NameError when `digest/sha2` library isn't loaded by another place.
So this patch adds a `require`.

nevesenin/graphql-ruby,nevesenin/graphql-ruby,nevesenin/graphql-ruby,rmosolgo/graphql-ruby,nevesenin/graphql-ruby,rmosolgo/graphql-ruby,rmosolgo/graphql-ruby,rmosolgo/graphql-ruby