This driver implemented get_pending_updates and then carried
get_available_updates as a one-line alias, because netOrk's API only ever called
the latter. Two names for one thing, with the driver bridging the gap.
napalm-device-types v1.0 collapses them onto get_available_updates — the name
four drivers and every netOrk call site already used — so the alias has nothing
left to bridge.
BREAKING CHANGE: get_pending_updates is gone; call get_available_updates.
The seven pre-existing test failures in this repo are untouched and unrelated;
see netork#110.