add redis cluster client tests

[leeym]

I should have done this in https://github.com/mennanov/limiters/pull/48, but I think it is not too late to do it now.

The existing test environment only has single node Redis and there is no Redis cluster. Given that the Redis and Redis cluster may behave differently, I think we should test them separately.

• keep Redis at port 6379 while adding Redis cluster at port 7000-7005
• whenever we test Redis, we test Redis cluster as well

Also run it in two separate builds:

• remove hash tags in redisKey to reproduce the error message CROSSSLOT ...
• add hash tags back in redisKey to show that it works

[leeym]

Not sure why there are only two checks and no tests executed. Close this PR and recreate one.