add free ebook notification

Author: Packt-ITService

README.md

@@ -1,2 +1,6 @@
 # Hands-On Data-Structures-and-Algorithms-with-Python-Third-Edition-published-by-Packt
 Hands-On Data Structures and Algorithms with Python – Third Edition
+### Download a free PDF
+
+ <i>If you have already purchased a print or Kindle version of this book, you can get a DRM-free PDF version at no cost.<br>Simply click on the link to claim your free PDF.</i>
+<p align="center"> <a href="https://packt.link/free-ebook/9781801073448">https://packt.link/free-ebook/9781801073448 </a> </p>