PHP Fatal error: Class 'Pimple\Container' not found after upgrading to 18.0.10

Nextcloud version (eg, 18.0.2): 18.0.10
Operating system and version (eg, Ubuntu 20.04): 18.04.5
Apache or nginx version (eg, Apache 2.4.25): 1.15.5
PHP version (eg, 7.1): 7.2.24

The issue you are facing:

After upgrading from nextcloud 18.0.6 to 18.0.10 the browser shows only a white site if I try to access my nextcloud. If I try to run “sudo -u www-data php occ maintenance:repair” (or any other occ-command), the terminal shows me the following error message:

PHP Fatal error: Class ‘Pimple\Container’ not found in /var/www/nextcloud/lib/private/AppFramework/Utility/SimpleContainer.php on line 44

What can I do? Thanks so much for you help!