add free ebook notification

Author: Packt-ITService

README.md

@@ -60,3 +60,7 @@ Hayden is the author of a series of machine learning books and an education enth
 
 
 
+### 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/9781800209718">https://packt.link/free-ebook/9781800209718 </a> </p>