Feature Request: Improved Support/Documentation for PipelineModel

While an example includes use of PipelineModel: https://github.com/aws/aws-step-functions-data-science-sdk-python/blob/main/src/stepfunctions/template/pipeline/inference.py#L128

This is a no-op: https://github.com/aws/aws-step-functions-data-science-sdk-python/blob/main/src/stepfunctions/template/pipeline/inference.py#L142

Setting the parameters property results in no changes to the CreateModel API call.
Instead, this method should be called: https://github.com/aws/aws-step-functions-data-science-sdk-python/blob/master/src/stepfunctions/steps/states.py#L201

which performs the desired update: self.fields[Field.Parameters.value] = params

Overall, while the example should likely be updated and documentation provided on use of PipelineModel, this method of parameter updating feels like a workaround. Ideally, ModelStep could take PipelineModel as input.

src/stepfunctions/template/pipeline/inference.py の PipelineModel の例と no-op parameters プロパティから始め、次に src/stepfunctions/steps/states.py のパラメータ更新と比較します。PipelineModel と ModelStep の意図された関係を判断し、例とドキュメントを更新して、パラメータの変更が CreateModel API 呼び出しに反映されるようにします。

索引モデルが issue の本文から書いたものです。