packaging: always execute builddeb from source root Without this, dockerdeb and the make targets that invoke it may fail depending on the pwd at the time of invocation.

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