Add Release API Endpoints for Groups

Overview

Often users want to fetch all of the Releases from all subsequent projects at a specific group, but we only have project-level API today. We should add group-level API as well.

This endpoint can also be used for the endpoint refactoring in the future.

Implementation plan

• Create one Grape API endpoint for getting Releases for all projects within a group
  • See current implementation for things we might want to reuse
• Requirements:
  • Should be possible to order by created_at: :desc
  • Return at least id and tag fields
  • Pagination
• To test compatibility with frontend, the new API path can be passed to the frontend here: https://gitlab.com/gitlab-org/gitlab/-/blob/master/app/helpers/search_helper.rb#L356
  • See example usage below

Example usage

Current endpoint: https://gitlab.com/groups/gitlab-org/-/releases.json

Release notes

We have added a new endpoint for the Groups API that allows releases to be retrieved for all projects within a group.