API gateway http-proxy integration header configuration

I am using API Gateway as a proxy for my backend service. I am trying to configure it by using a serverless framework. I have custom authorizer (lambda function) to verify the incoming request and extracting data from JWT token and passing it to my backend service.

I am facing issue in passing integration headers as shown in below image.

Here is the serverless.yaml file

service: api-gateway-serverless-test
plugins:
  - serverless-iam-roles-per-function
provider:
  name: aws
  runtime: nodejs12.x
  stage: dev
  profile: latlong
functions:
  agora:
    handler: agora.agora
    events:
      - http:
          path: agora/{proxy+}
          method: ANY
          cors: true
          authorizer: aws_iam
          integration: http-proxy
          request:
            uri: 'http://agora-service.dev.freighttiger.com/agora/{proxy}'
            parameters:
              paths:
                proxy: true
              headers:
                'x-entity-type': context.authorizer.entity_type
                'x-ft-userid': context.authorizer.user_id