```release-note:enhancement
resource/aws_elastictranscoder_pipeline: Add plan time validations to `content_config.storage_class`, `content_config_permissions.access`, `content_config_permissions.grantee_type`,
`notifications.completed`, `notifications.error`, `notifications.progressing`, `notifications.warning`,
`thumbnail_config.storage_class`, `thumbnail_config_permissions.access`, `thumbnail_config_permissions.grantee_type`
```