Add back in reference to Colab Version

Author: Jessica Lin

intermediate_source/dynamic_quantization_bert_tutorial.rst

@@ -1,5 +1,9 @@
 (experimental) Dynamic Quantization on BERT
 ===========================================
+
+.. tip::
+   To get the most of this tutorial, we suggest using this 
+   `Colab Version <https://colab.research.google.com/github/pytorch/tutorials/blob/gh-pages/_downloads/dynamic_quantization_bert_tutorial.ipynb>`_. This will allow you to experiment with the information presented below.
 
 **Author**: `Jianyu Huang <https://github.com/jianyuh>`_