Plesk Git extension does not pull from GitHub: Method name must be a string

The following error message is logged in the /var/log/plesk/panel.log with debug mode enabled:

CONFIG_TEXT: DEBUG [extension/git] Error: Method name must be a string in /opt/psa/admin/plib/modules/git/library/Deployer/Steps.php:107
Stack trace:
#0 [internal function]: PleskExt\Git\Deployer\Steps->PleskExt\Git\Deployer\{closure}()
#1 /opt/psa/admin/plib/modules/git/library/Helper/ExtensionContext.php(19): call_user_func(Object(Closure))
#2 /opt/psa/admin/plib/modules/git/library/Deployer/Steps.php(108): PleskExt\Git\Helper\ExtensionContext::callWithExtensionContext('laravel', Object(Closure))
#3 /opt/psa/admin/plib/modules/git/library/Deployer/Steps.php(80): PleskExt\Git\Deployer\Steps->addPluginsSteps('validate_deploy...')
#4 /opt/psa/admin/plib/modules/git/library/Deployer/Steps.php(61): PleskExt\Git\Deployer\Steps->initSteps()
#5 /opt/psa/admin/plib/modules/git/library/Deployer/Deployer.php(26): PleskExt\Git\Deployer\Steps->__construct(Object(PleskExt\Git\DTO\Repository))
#6 /opt/psa/admin/plib/modules/git/controllers/ApiController.php(288): PleskExt\Git\Deployer\Deployer->__construct(Object(PleskExt\Git\Db\Repository))
#7 /opt/psa/admin/plib/vendor/plesk/zf1/library/Zend/Controller/Action.php(516): ApiController->repositoryPullAction()
#8 /opt/psa/admin/plib/modules/git/controllers/ApiController.php(113): Zend_Controller_Action->dispatch('repositoryPullA...')
#9 /opt/psa/admin/plib/vendor/plesk/zf1/library/Zend/Controller/Dispatcher/Standard.php(308): ApiController->dispatch('repositoryPullA...')
#10 /opt/psa/admin/plib/vendor/plesk/zf1/library/Zend/Controller/Front.php(954): Zend_Controller_Dispatcher_Standard->dispatch(Object(Zend_Controller_Request_Http), Object(Zend_Controller_Response_Http))
#11 /opt/psa/admin/plib/pm/Application.php(87): Zend_Controller_Front->dispatch()
#12 /opt/psa/admin/htdocs/modules/git/index.php(5): pm_Application->run()
#13 {main}