redis-benchmark with --cluster

[phanirithvij]

redis-benchmark with --cluster option while using redisraft with the example from in the readme (1 leader and two members) fails because there is a check that is requiring 2 or more leaders in redis-benchmark code

https://github.com/redis/redis/blob/44cc0fcb9d8bfa194f65f306bce7f91d17ada2ed/src/redis-benchmark.c#L1808-L1812

Changing it from <= 1 to < 1 and recompiling works.

I used the memtier_benchmark as it is what is being used to benchmark this project, it works fine with --cluster option.

https://github.com/RedisLabs/redisraft/blob/ade4aa8e6aa5c3b21678a1998309825f06567d4f/benchmark/benchmark.json#L4C20-L4C20

(Wasn't sure where to open the issue, thought here would be better as I believe the discussion belongs here? Idk. Also I have never used redis cluster before, only experimenting with redisraft for the first time and thus I am not sure why the 2 or more master restriction exists)