Durations in Fs2RabbitConfig

[DStranger]

Hi guys!

Fs2RabbitConfig currently uses ints for durations, which is confusing:
connectionTimeout is defined in milliseconds,
requestedHeartbeat is defined in seconds.

Moreover, official examples use a very low value for connectionTimeout (3), which causes issues when being used in real environments, and adds to the confusion.

This can be solved in multiple ways, but I think the best solution would be to be able to specify durations as such (10 s, etc).
This would introduce some backward compatibility problems, so I'm curious what you think.

[jbwheatley]

fixed in 4.0.0 (requires cats-effect 3)