Chalice generate-pipeline creates new API instead of updating previous API

Greetings,

My previous deployments have been using the chalice deploy command simply. I tried to switch to code pipeline to move forward to automated pipelines. I ran the chalice generate-pipeline command with GitHub support and later ran cloud formation to deploy the stack. I did create all of the pipelines, but i didn't update my previous API, instead, it created a new API in API gateway with a new set of lambda functions.

Start by reproducing the deployment flow described: run chalice generate-pipeline with GitHub support, then deploy the resulting CloudFormation stack after an existing chalice deploy. Trace how the pipeline identifies the existing API and Lambda functions; done means the automated deployment updates them rather than creating a second API and new functions.

Written by the indexing model from the issue text.