Fix RTD link in TF README (#629)

Author: laurenyu

src/sagemaker/tensorflow/README.rst

@@ -165,7 +165,7 @@ Required argument
 
   - ``str``: An S3 URI, for example ``s3://my-bucket/my-training-data``, which indicates the dataset's location.
   - ``dict[str, str]``: A dictionary mapping channel names to S3 locations, for example ``{'train': 's3://my-bucket/my-training-data/train', 'test': 's3://my-bucket/my-training-data/test'}``
-  - ``sagemaker.session.s3_input``: channel configuration for S3 data sources that can provide additional information as well as the path to the training dataset. See `the API docs <https://sagemaker.readthedocs.io/en/latest/session.html#sagemaker.session.s3_input>`_ for full details.
+  - ``sagemaker.session.s3_input``: channel configuration for S3 data sources that can provide additional information as well as the path to the training dataset. See `the API docs <https://sagemaker.readthedocs.io/en/stable/session.html#sagemaker.session.s3_input>`_ for full details.
 
 Optional arguments
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