Getting 403 Status when following the code in `order-update.js` file

[j-a-h-i-r]

I was following the guide on sending updates to created order on Google Actions documentation. The documentation pointed to this repository, specifically order-update.js file for an example order update operation.

I created a service account key on my account. When I tried to update a created order following the code in the order-update.js file, I got a 403 status code in return.

Did the steps for this operation change? How can I perform an order update successfully?