Update to 1.11.0: Failed opening required '/PATH/apps/workflow_script/composer/../vendor/autoload.php' in occ

[nursoda]

On my NC26beta5 test instance occ app:update --all just yielded

workflow_script new version available: 1.11.0
An unhandled exception has been thrown:
Error: Failed opening required '/PATH/apps/workflow_script/composer/../vendor/autoload.php' (include_path='/PATH/3rdparty/pear/archive_tar:/PATH/3rdparty/pear/console_getopt:/PATH/3rdparty/pear/pear-core-minimal/src:/PATH/3rdparty/pear/pear_exception:/PATHapps') in /PATH/apps/workflow_script/composer/autoload.php:5
Stack trace:
#0 /PATH/lib/private/legacy/OC_App.php(295): require_once()
#1 /PATH/lib/private/legacy/OC_App.php(1013): OC_App::registerAutoloading()
#2 /PATH/lib/private/Installer.php(200): OC_App::updateApp()
#3 /PATH/core/Command/App/Update.php(107): OC\Installer->updateAppstoreApp()
#4 /PATH/3rdparty/symfony/console/Command/Command.php(255): OC\Core\Command\App\Update->execute()
#5 /PATH/3rdparty/symfony/console/Application.php(1009): Symfony\Component\Console\Command\Command->run()
#6 /PATH/3rdparty/symfony/console/Application.php(273): Symfony\Component\Console\Application->doRunCommand()
#7 /PATH/3rdparty/symfony/console/Application.php(149): Symfony\Component\Console\Application->doRun()
#8 /PATH/lib/private/Console/Application.php(215): Symfony\Component\Console\Application->run()
#9 /PATH/console.php(100): OC\Console\Application->run()
#10 /PATH/occ(11): require_once('...')
#11 {main}