Missing .gitignore files
If you downloaded a compressed archive, there might have been missing
.gitignore files that prevent the upgrade from completing properly. To apply our update, patch
magento/magento-composer-installer then run
composer update from your Magento installation directory.
The following figure shows an example of this issue when using the Setup Wizard.
To solve this issue:
- Log in to your Magento server as the Magento file system owner.
- Change to your Magento installation directory.
Run the following commands in the order shown:
composer update magento/magento-composer-installer composer update
- Try your upgrade again.