Allow SDKAlias to use nested objects for physical id and return values

[toshke]

Enhancements

In SDKAlias function, if object returned from API is more than 1 level deep, it was not possible to get nested object properties. Concrete example that I needed this functionality for is writing custom resource for creating AmazonCognito User Pool Client, where response data is nested under UserPoolClient map. (Example below)

Create: CfnLambda.SDKAlias({
    api: CognitoApi,
    method: 'createUserPoolClient',
    returnAttrs: [
      'UserPoolClient.ClientId',
      'UserPoolClient.CreationDate',
      'UserPoolClient.LastModifiedDate'
    ],
    returnPhysicalId: 'UserPoolClient.ClientId'
  }),

This pull request allows pulling physicalResourceId and query-able properties with Fn::GetAtt by using dot notation to select nested object properties from SDK call result.

Updated aws-sdk version

Essentially, feature above is being tested with custom resource for Amazon Cognito User Pool Client management. Without bumping up the aws-sdk version, I would get parameter validation errors

Fix

In SDKAlias section, README shows returnKeys as option key to define which API response fields should be mapped to data accessible with Fn::GetAtt cfn function. However, looking at the source code itself, seems like returnAttrs is actual key being used. README has been updated to reflect reality of the source code

[andrew-templeton]

I've got a bunch of work today but I'll be deploying this into main-line. Good idea!

[toshke]

@andrew-templeton great, looking forward to it - this way I don't have to link vendored version in package.json, thanks!

[toshke]

@andrew-templeton any updates on this, any chance this gets published?