Providers with yield

[provinzkraut]

On a reddit post someone brought up supporting generator based providers, so that cleanup code could be run after the request.

[Goldziher]

i think this is a pretty neat idea, i dont see a reason we shouldnt implement this support - its like pytest. What do you think?

[provinzkraut]

I think we should support this. It's an established pattern in python and shouldn't be too difficult to implement.

[provinzkraut]

Implemented in #856