What is the status of NotebookRunnerStep?

[This question came up on SO](https://stackoverflow.com/questions/63866007/trigger-jupyter-notebook-in-azure-ml-workspace-from-adf/63878663#63878663​​​​​​​), and it made me think of `NotebookRunnerStep`. the SDK docs make no mention of `NotebookRunnerStep` but there is a demo notebook in this repo. Is that because the feature is still in public preview? If so, what's the roadmap to GA or inclusion in the main SDK (at least the docs?).

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* ID: 2cf9e3d1-b313-c997-eae8-6cab3bd2014a
* Version Independent ID: 0ef18191-46b9-6da0-0951-627a442c7d5e
* Content: [azureml.pipeline.steps package - Azure Machine Learning Python](https://docs.microsoft.com/en-us/python/api/azureml-pipeline-steps/azureml.pipeline.steps?view=azure-ml-py)
* Content Source: [AzureML-Docset/stable/docs-ref-autogen/azureml-pipeline-steps/azureml.pipeline.steps.yml](https://github.com/MicrosoftDocs/MachineLearning-Python-pr/blob/live/AzureML-Docset/stable/docs-ref-autogen/azureml-pipeline-steps/azureml.pipeline.steps.yml)
* Service: **machine-learning**
* Sub-service: **core**
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* Microsoft Alias: **debfro**