I'm using a site created on Pantheon and now I'm not using pantheon.
So the core is not installed with composer. Now I want to upgrade core with composer but I don't understand how.
I've some modules installed with composer, so I try to add drupal/core :
compose require "drupal/core"
It's ok, but if I try to this, the aren't upgrades:
composer update drupal/core --with-dependencies
I've core 8.6.1 and I wanto to update to 8.6.2.