Append : to ns

[t4sk]

rsmq (js) appends : to ns

https://github.com/smrchy/rsmq/blob/5c507c2ae97145fbdef7369da52dc69b105e0cc6/_src/index.ts#L62

Here is the example of queues created in rust implementation and JS.
Redis keys without : between ns and queue name are created by this rust implementation.
Ones with : are created by JS implementation.

> redis-cli --scan --pattern '*'
rsmq:QUEUES
rsmqQUEUES
rsmqtest:Q
rsmq:test:Q

This implementation does not. So this PR changes the code to align the queue name with rsmq (js)

[DavidBM]

Thanks for the MR! I will make a couple of changes and I'm happy to merge it!

[DavidBM]

Merged as is. Thanks for that! 🙇 I will publish it under version 10 of the crate