Invalid dash-separated options for description-file

[wickeat]

Describe the feature you'd like
To rename the description file in

sagemaker-training-toolkit/setup.cfg

to description_file.
This is to avoid the setuptools warning of SetuptoolsDeprecationWarning: Invalid dash-separated options, when installing this package. An example of the error is shown below.

  C:\projects\.venv\Lib\site-packages\setuptools\dist.py:745: SetuptoolsDeprecationWarning: Invalid dash-separated options
  !!

          ********************************************************************************
          Usage of dash-separated 'description-file' will not be supported in future
          versions. Please use the underscore name 'description_file' instead.

          This deprecation is overdue, please update your project and remove deprecated
          calls to avoid build errors in the future.

          See https://setuptools.pypa.io/en/latest/userguide/declarative_config.html for details.
          ********************************************************************************