docs(tutorial): fix pip package name mistake

[wenyuan]

while running command pip install, the package name is channels-redis instead of channels_redis.
ref: https://pypi.org/project/channels-redis/

[carltongibson]

AFAICS it works fine as it is:

 % pip install channels_redis
Collecting channels_redis
  Downloading channels_redis-4.1.0-py3-none-any.whl (18 kB)

[... snip ...]

Installing collected packages: msgpack, typing-extensions, sqlparse, async-timeout, redis, asgiref, Django, channels, channels_redis
Successfully installed Django-4.2.4 asgiref-3.7.2 async-timeout-4.0.3 channels-4.0.0 channels_redis-4.1.0 msgpack-1.0.5 redis-5.0.0 sqlparse-0.4.4 typing-extensions-4.7.1

[wenyuan]

AFAICS it works fine as it is:

 % pip install channels_redis
Collecting channels_redis
  Downloading channels_redis-4.1.0-py3-none-any.whl (18 kB)

[... snip ...]

Installing collected packages: msgpack, typing-extensions, sqlparse, async-timeout, redis, asgiref, Django, channels, channels_redis
Successfully installed Django-4.2.4 asgiref-3.7.2 async-timeout-4.0.3 channels-4.0.0 channels_redis-4.1.0 msgpack-1.0.5 redis-5.0.0 sqlparse-0.4.4 typing-extensions-4.7.1

Got it. Thank you for your reply!