Update to redis-rs 0.9

[maximshe]

Hi,

I found that serde-redis is not working with latest redis-rs crate.

Now in code version is limited with: redis = "> 0.5, < 0.9".
I run a local testing with redis set to 0.9.0 and everything works fine for me.

If it's ok, I would suggest a patch with change to redis = "> 0.5, < 1.0".