Instead of maintaining multiple interface for grouping
owner name and repo name, we expose a shared interface
describing a Github repository.
One unfortunate downside is that the GraphQL Github
and Rest API diverge slightly with the key for the
repository name. i.e. rest uses `repo` for the name
of a repository, while GraphQL uses `name` for the name.
If that would be consistent, we could use the rest operator
to pass a repository to the Octokit REST or GraphQL API. This
does not work, so we have a small manual overhead as seen
in the `branches.ts` file.
PR Close#38656