Add author to data loading tutorial

Author: chsasank

beginner_source/data_loading_tutorial.py

@@ -2,6 +2,7 @@
 """
 Data Loading and Processing Tutorial
 ====================================
+**Author**: `Sasank Chilamkurthy <https://chsasank.github.io>`_
 
 A lot of effort in solving any machine learning problem goes in to
 preparing the data. PyTorch provides many tools to make data loading