Missing an await in export-users-in-group

[tvkit]

lambda terminating prior to completion of ddb batch-write operation

https://github.com/aws-solutions/cognito-user-profiles-export-reference-architecture/blob/a923a3317b46de8dc9f4076ce15b667f89390262/source/workflow-export/export-users-in-group.js#L59

The following await can be applied directly within the lambda for deployments that rely on the existing unawaited behavior. The diff was performed on a fork of this repo.

[mikeols]

Thank you, @tvkit. The team is looking closer at this issue. It does look like there should be an await there.