```release-note:enhancement
data-source/aws_elasticache_cluster: Add `cache_nodes.outpost_arn` and `preferred_outpost_arn` attributes
```

```release-note:enhancement
resource/aws_elasticache_cluster: Add `outpost_mode` and `preferred_outpost_arn` arguments and `cache_nodes.outpost_arn` attribute. NOTE: Because we cannot easily test this functionality, it is best effort and we ask for community help in testing
```