Simplify repository config

[pi0]

Instead of 3 separate options, { owner: 'nuxt', repo: 'image', branch: 'main' } we could support repository: 'nuxt/image#main'

[Tahul]

Taking this up for next versions;

Any preferred way to parse that string @pi0? Maybe we could support both syntaxes?

[pi0]

Supporting object syntax makes sense too. Personally, i use simplified repo: 'owner/name' for unjs packages and parse it when needed as most of the the times, the combination is consumed. Also instead of branch, we could call it ref (ref can be also a git tag or commit)