Support Ref/GetAtt for local function names

[theburningmonk]

We recently added support to the serverless-step-functions plugin to let you use Ref/GetAtt with the local function names (declared by the user in their serverless.yml, e.g. hello-world) as well as the CloudFormation local IDs (generated by the serverless framework, e.g. HelloDashworldLambdaFunction).

It was one of those things that newcomers to the serverless framework and CloudFormation struggle with, as they have to juggle with two sets of concepts and need to know underlying implementation details in the Serverless framework.

Someone mentioned to me that they experienced similar pain points in this plugin so I thought I'd leave a note here in case it's a feature you'd be interested in. I've not done much with AppSync but happy to help you put this in.