Only does this if the repo config (i.e. the main, next and dev branches) are detailed in the
.git-next.toml file within the repo, rather than in the git-next-server.toml file.
Closeskemitix/git-next#74
The `git push` command requires a git directory (bare at a minimum)
before it can work.
The git dir must also be up-to-date with the relevant references from
the remote, so
we do a `git fetch` before a `git push`.
Closeskemitix/git-next#51
The user can specify a gitdir for a repo in the `git-next-server.toml` file.
When they do, then we should use that directory.
Closeskemitix/git-next#71
