Update README to make Step 1 clearer
Update README to make Step 1 clearer

The current instructions for running the consumer in Step 1 assume that a provider is also running, but don't make it clear how to do this -- see [Issue #4](https://github.com/DiUS/pact-workshop-jvm/issues/4)

I've added an extra step to make running of the dropwizard-provider explicit.

DiUS/pact-workshop-jvm