title: AWS CDK Deploying to stage without deleting previous stages
body: <p>I'm using AWS CDK to manage deployments of my API Gateway. I use stages to promote my code through environments, e.g. DEV, TEST, PREPROD, PROD. My script looks something like this:</p>
  <pre><code>export class MyStack extends cdk.Stack {
    constructor(scope: cdk.Construct, id: string, props?: cdk.StackProps) {
      super(scope, id, props);
  
      const api = new apigateway.SpecRestApi(this, 'my-api', {
        deploy: false,
        apiDefinition: apigateway.ApiDefinition.fromAsset('path/to/swagger.yaml'),
      });
  
      const stageName = this.node.tryGetContext('stageName');
  
      const deployment = new apigateway.Deployment(this, `my-api-deployment-${stageName}`, { api });
      new apigateway.Stage(this, `my-api-stage-${stageName}`, {
          stageName,
          deployment,
      });
    }
  }
  </code></pre>
  <p>Unfortunately, when I promote my code from one stage to the next, e.g. <code>cdk deploy --context stageName=PREPROD</code>, previous stages are deleted, so I only end up with a single stage in my API Gateway.</p>
  <p>Is it possible to deploy to a stage without deleting the other stages?</p>