2.0.0 RC1

This release provides compatibility with amphp/redis@v1.

Note: This is a pre-release, there might be breaking changes in the final stable version.

Some BC breaks were required for compatibility in RedisStorage.

• RedisStorage constructor now requires an instance of Amp\Redis\Redis and Amp\Redis\Mutex\Mutex.
• RedisStorage::getClient() now returns an instance of Amp\Redis\Redis.

The rest of the API remains unchanged, so only changes to Redis storage initialization should be required when upgrading from v1.x.