fix: fix schema update failure (#655)

Resolves #654

Author: joerivanveen

Setup/UpgradeData.php

@@ -624,6 +624,7 @@ public function upgrade(ModuleDataSetupInterface $setup, ModuleContextInterface
                 $connection->insert($table, $bind);
             }
             $insuranceBelgium = 'myparcelnl_magento_postnl_settings/default_options/insurance_belgium_active';
+            $connection->delete($table, ['path = ?' => $insuranceBelgium]);
             $connection->insert($table, ['path' => $insuranceBelgium, 'value' => 1]);
         }
         $setup->endSetup();