* Newer pip install command from git
Updated cutting edge pip install command to use HTTPS rather than insecure git+git protocol, as recommended by pip documentation. This allows the command to work with pip >= 21.0.1
* Updated pip command in README
* modify zadd calls for redis-py 3.0
redis-py 3.0 changes the zadd interface that accepts a single
mapping argument that is expected to be a dict.
https://github.com/andymccurdy/redis-py#mset-msetnx-and-zadd
* change FailedQueue.push_job_id to always push a str
redis-py 3.0 does not attempt to cast values to str and is left
to the user.
* remove Redis connection patching
Since in redis-py 3.0, Redis == StrictRedis class, we no longer
need to patch _zadd and other methods.
Ref: https://github.com/rq/rq/pull/1016#issuecomment-441010847
James Cobb