Pointing deployment to aliases and pulling original env variables #142

Hi @nficano !

Really love this package. My team currently uses it and its added a lot of much needed structure to our lambda creation and deployment process. There's a feature we've been trying to determine if it is already implemented but haven't been able to confirm whether or not its supported:

We have multiple users who work on our lambda functions. In our config files, we don't specify environment variables directly to avoid having them directly in code. Instead, we reference our own local environments.

The issue here is that as our team gets larger, sometimes the environment variables we have locally don't always match or don't match the ones that already live on the lambda function. I'm curious --> if we have an existing lambda function that already has environment variables specified in AWS, is there a way to deploy so that the environment variables, even if the ones we are using locally are different? If not, is there a way we can reference the environment variables already specified in the lambda function?

Hope this makes sense. Thanks in advance for any help =).