Update README.md

Link to image as release attachement

Author: DanielaSchacherer

notebooks/pathomics/README.md

@@ -1,5 +1,5 @@
 # Introduction to working with digital pathology images in IDC
-<img src="patho_images.jpeg" width="1000"/>
+<img src="https://github.com/ImagingDataCommons/IDC-Tutorials/releases/tag/0.20.0/patho_images.jpeg" width="1000"/>
 
 ## Repository content
 This repository contains