docs: def update_command(args):
      """Updates all dependencies the specified requirements file."""
      updated = update_requirements_file(
          args.requirements_file, args.skip_packages)
  
      if updated:
          print('Updated requirements in {}:'.format(args.requirements_file))
  
          for item in updated:
              print(' * {} from {} to {}.'.format(*item))
      else:
          print('All dependencies in {} are up-to-date.'.format(
              args.requirements_file))