Liberal dependency breaks after release of redis-3.0.0

[0x64746b]

With the release of the backwards incompatible Redis bindings v3.0.0, the dependency >= 2.10.5 breaks:

[2018-11-15 14:55:10,898: CRITICAL/MainProcess] Unrecoverable error: AttributeError("'float' object has no attribute 'items'",)
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/celery/worker/worker.py", line 205, in start
    self.blueprint.start(self)
  File "/usr/local/lib/python3.6/site-packages/celery/bootsteps.py", line 119, in start
    step.start(parent)
  File "/usr/local/lib/python3.6/site-packages/celery/bootsteps.py", line 369, in start
    return self.obj.start()
  File "/usr/local/lib/python3.6/site-packages/celery/worker/consumer/consumer.py", line 317, in start
    blueprint.start(self)
  File "/usr/local/lib/python3.6/site-packages/celery/bootsteps.py", line 119, in start
    step.start(parent)
  File "/usr/local/lib/python3.6/site-packages/celery/worker/consumer/consumer.py", line 593, in start
    c.loop(*c.loop_args())
  File "/usr/local/lib/python3.6/site-packages/celery/worker/loops.py", line 91, in asynloop
    next(loop)
  File "/usr/local/lib/python3.6/site-packages/kombu/asynchronous/hub.py", line 354, in create_loop
    cb(*cbargs)
  File "/usr/local/lib/python3.6/site-packages/kombu/transport/redis.py", line 1040, in on_readable
    self.cycle.on_readable(fileno)
  File "/usr/local/lib/python3.6/site-packages/kombu/transport/redis.py", line 337, in on_readable
    chan.handlers[type]()
  File "/usr/local/lib/python3.6/site-packages/kombu/transport/redis.py", line 724, in _brpop_read
    self.connection._deliver(loads(bytes_to_str(item)), dest)
  File "/usr/local/lib/python3.6/site-packages/kombu/transport/virtual/base.py", line 983, in _deliver
    callback(message)
  File "/usr/local/lib/python3.6/site-packages/kombu/transport/virtual/base.py", line 632, in _callback
    self.qos.append(message, message.delivery_tag)
  File "/usr/local/lib/python3.6/site-packages/kombu/transport/redis.py", line 149, in append
    pipe.zadd(self.unacked_index_key, time(), delivery_tag) \
  File "/usr/local/lib/python3.6/site-packages/redis/client.py", line 2263, in zadd
    for pair in iteritems(mapping):
  File "/usr/local/lib/python3.6/site-packages/redis/_compat.py", line 123, in iteritems
    return iter(x.items())
AttributeError: 'float' object has no attribute 'items'

Downgrading to redis==2.10.6 fixes the problem

[geoffreybauduin]

redis/redis-py#1068

[auvipy]

this is now fixed in master