Update nats example

[AlexCuse]

Maybe we could provide in a _example directory in this repo for simplicity but thinking about this one:

https://github.com/ThreeDotsLabs/nats-example

[VeryStrongFingers]

I've created a relevant PR ThreeDotsLabs/watermill#278

[AlexCuse]

Thanks for this @VeryStrongFingers - regarding your note on stability I do have a draft PR in the watermill-nats repo that could upset the apple cart a little. But I think leave all this in a better place long term.

I was thinking of something that lives inside this repo that can be used as a test harness for local changes using replace - see https://github.com/AlexCuse/watermill-nats/tree/master/_examples. The linked example in the original issue is a bit more built out but the examples you point to are a super quick way to get there and work the system just fine for our purposes.