Allow to query users by other identifiers than external Ids

[abraxxas]

Currently the library expects always external ids for the export user by ID endpoint. Would you be open to PR to change this behaviour to also allow querying by alias and other options as well?

The specific line in question is linked below. It seems to be a rather easy fix to me but i would need to check since i am not too familiar with ruby

braze_ruby/lib/braze_ruby/rest/export_users.rb

Line 16 in 5f4c02f

external_ids: external_ids

[jonallured]

You're referring to this endpoint, right?

https://www.braze.com/docs/api/endpoints/export/user_data/post_users_identifier/

Yeah I'd be open to a PR that more closely matches how that endpoint works. 👍