Redis Cluster support.

[lsk569937453]

Could you support the url of redis-cluser?

[hexcowboy]

I would accept a PR for this. Here is some relevant documentation from the redis crate https://docs.rs/redis/latest/redis/cluster/index.html

[ZaraGiraffe]

I have created my own version from your rslock that works only with ClusterConnection. Are you interested?

[hexcowboy]

@ZaraGiraffe feel free to open a pull request if you'd like