account_timelines: fix default ordering of events

Signed-off-by: Pierre-Alexandre Meyer <pierre@mouraf.org>
killbill_helper: update bundle & subscription APIs to killbill-client-ruby

Signed-off-by: Pierre-Alexandre Meyer <pierre@mouraf.org>
Gemfile.lock: update dependencies

Signed-off-by: Pierre-Alexandre Meyer <pierre@mouraf.org>
chargebacks: add option to cancel subscriptions

Signed-off-by: Pierre-Alexandre Meyer <pierre@mouraf.org>