feat: Added new attributes for fork endpoint

[maicol07]

Reference: https://docs.gitlab.com/ee/api/project_forks.html#fork-a-project

[MagnusHJensen]

Hey man, this is something I definitely could use right now.

Are you up for fixing the conflicts, but also not breaking the style guide? If not then I can make a new PR instead.

[maicol07]

Hey man, this is something I definitely could use right now.

Are you up for fixing the conflicts, but also not breaking the style guide? If not then I can make a new PR instead.

Hi, there aren't conflicts with the main branch of the original repo

[MagnusHJensen]

This PR fails with style conflicts, so yeah there is.

You have also modified the entire projects file where there is a string concat, so I would assume the authors/maintainers want that removed.

[maicol07]

Oh yes I can solve the style conflicts

[drumm]

This would be useful for me, too. It looks like the CI bot identified one remaining spacing issue.

I don't know if the maintainers will want to see the unrelated spacing-only changes in this PR.

[stale]

This issue has been automatically marked as stale because there has been no recent activity. It will be closed after 30 days if no further activity occurs. Thank you for your contributions.

[maicol07]

@GrahamCampbell can you reopen this?

[maicol07]

Rebased on 12.0 in #841