.arcconfig

automation: install Python 2.7.17, 3.7.5, and PyPy 7.2.0

These were all recently released and we should use them in
automation.

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