Model version should be a string

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Hi, great service, but why is model 'version' limited to int? We would like to use major.minor.patch numbering for instance. Thank you and best regards.

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#### Document Details

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* ID: 08d33267-fb2b-bc8a-1b61-50122b944dd1
* Version Independent ID: 17c92047-89c8-0881-6d9f-235f50a2d5af
* Content: [azureml.core.model.Model class - Azure Machine Learning Python](https://docs.microsoft.com/en-us/python/api/azureml-core/azureml.core.model.model?view=azure-ml-py)
* Content Source: [AzureML/docs-ref-autogen/azureml-core/azureml.core.model.Model.yml](https://github.com/MicrosoftDocs/MachineLearning-Python-pr/blob/live/AzureML/docs-ref-autogen/azureml-core/azureml.core.model.Model.yml)
* Service: **machine-learning**
* Sub-service: **core**
* GitHub Login: @j-martens
* Microsoft Alias: **jmartens**