How do you stop an update on an Xbox One Game?

To stop an update:

1. Go to your My games and Apps section on your Xbox
2. Navigate to the Queue section on the left and find the game being updated on the right (Doom in this case).
3. Press the Menu button on your controller and select Cancel. This will stop the update process.

Source: Xbox Support Page, as well as experience.

Note that I am unsure if you will be able to play the game offline. I'm not sure how physical disc copies of games work, but I believe that in order to play any digitally owned game, they must be kept up to date (I could be wrong).

Don’t try to cancel an update. If you cancel an update that has started, it will delete the whole game and its data. Found out the hard way today.