Update the example health check

[IngmarStein]

With a check as part of the image, users don't have to configure the checks themselves in a Compose file, for example.

[klutchell]

Hey @IngmarStein , this image actually used to have a default health check but it was removed as it caused more issues and confusion than it solved.

In my experience, health checks are best left to those that are defining the runtime via compose, not the image itself. Otherwise the image may fail for environmental reasons with little explanation.

That said, I appreciate the fix in the example compose file so I agree we should merge that part!

[IngmarStein]

Alright, I've removed the change to Dockerfile and kept the updated example.