v0.9.8

• Fix shuttle-parking_lot's RwLock blocking plain readers when a second upgradable reader waits behind an existing upgradable read. Upgradable reads use the new BatchSemaphore::acquire_bypassable, so read and try_read can take available permits while the second upgradable read waits. (#400)

• Publish shuttle-engine 0.1.6, shuttle 0.9.8 and shuttle-parking_lot-impl 0.1.3. shuttle now requires shuttle-engine 0.1.6, and the parking_lot implementation requires shuttle 0.9.8 or later, so updating the implementation also brings in the new semaphore API. shuttle-parking_lot stays at 0.12.5 and picks up the fix through its existing ^0.1.0 implementation dependency.