Use correct pytorch-env.yml filename instead of pytorch-aml-env.yml

tiny change to save people from a headache when using the tutorial. 
pytorch-aml-env.yml does not exist at this point of the tutorial. 
replace with the correct existing filename: pytorch-env.yml.
or rename all the conda env files of the tutorial to pytorch-aml-env.yml for consistency.

Author: moutai

articles/machine-learning/tutorial-1st-experiment-sdk-train.md

@@ -363,7 +363,7 @@ Make sure you save this file before you submit the run.
 
 ### <a name="submit-again"></a> Submit the run to Azure Machine Learning
 
-Select the tab for the *run-pytorch.py* script, then select **Save and run script in terminal** to re-run the *run-pytorch.py* script.  Make sure you've saved your changes to `pytorch-aml-env.yml` first.
+Select the tab for the *run-pytorch.py* script, then select **Save and run script in terminal** to re-run the *run-pytorch.py* script.  Make sure you've saved your changes to `pytorch-env.yml` first.
 
 This time when you visit the studio, go to the **Metrics** tab where you can now see live updates on the model training loss! It may take a 1 to 2  minutes before the training begins.