.arcconfig

subrepo-git: use an official origvfs when appropriate

The origvfs has the auditor properly set and can move file without issue.

The current code is currently working without errors because rename are not
audited, yet.

{
    "conduit_uri": "https://phab.mercurial-scm.org/api",
    "repository.callsign": "HG",
    "arc.land.onto.default": "@",
    "base": "hg:.^"
}