ApiGateway ApiKeys are not working

This is a Bug Report

Description

when i set the apiKeys property inside provider, the plugin will create the keys but they are not applied to the Gateway.

For bug reports:

• What went wrong?
  ApiKey created, but not applied / working at the Gateway
• What did you expect should have happened?
  I need this ApiKey to access the Apigateway
• What was the config you used?

provider:
  name: aws
  apiKeys:
    - ${self:service}-${opt:stage, self:provider.stage}