infinitepush: opt out of changegroup3 unless explicitly configured
This is currently a no-op, as changegroup3 is disabled by default. But when it
is enabled, it changes the hash names of the bundle files. As I don't use this
extension, I have no idea if that's OK or not. So keep the current default
behavior until we can get more info from actual users, while allowing them to
opt-in for testing purposes.
{
"conduit_uri": "https://phab.mercurial-scm.org/api",
"phabricator.uri": "https://phab.mercurial-scm.org/",
"repository.callsign": "HG",
"arc.land.onto.default": "@",
"base": "hg:.^"
}