[gimie] Handle repository versioning

[cmdoret]

Currently, gimie sets the latest release of a repository as the version. This is not the correct way to handle versioning, as breaking changes can happen between the last release and HEAD. We need to allow users to refer to specific releases (tags).

The desired behaviour is as follows:

• gimie data <repo-url> -> empty version field (refers to HEAD)
• gime data <tag-url> -> set version field to tag (fixed version)

Objective: Record repository release only when specified by user.