How to update Drupal with Composer
Notes
With a Composer-installed Drupal project, it is possible to update your entire application with a single command and commit.
Checkout a new branch on your local project and run composer update
to update your dependencies.
Push to Platform.sh and then activate the environment to deploy the updated application.
Once the updates have passed all of your tests, you can merge and deploy the exact same updated application to production
in seconds.