Laravel config/app.php not updating

Seems like configuration settings were cached. use php artisan config:clear

Just a minor additional note to this. If you are running a local server on localhost:8000 with php artisan serve and you make changes to either your .env file or in config files, even after clearing the config cache with the steps in the accepted answer, it doesn't update.

You need to stop the local server (control + c in Terminal) and run php artisan serve to start it again - then your changes get picked up.