feat: Remove tutorial section from README

Removed tutorial section and related links from README.

Author: PierrickVoulet

node/project-management-app/README.md

@@ -13,12 +13,6 @@ stories (which represent features of a software system from the point of view of
 a user for the team to develop) and persists the stories in a
 [Firestore](https://cloud.google.com/firestore/docs) database.
 
-## Tutorial
-
-For detailed instructions to deploy and run this sample, follow the
-[dedicated tutorial](https://developers.google.com/chat/tutorial-project-management)
-in the Google Chat developer documentation.
-
 ## Scripts
 
 - `npm run test` : Executes all the unit tests.