Updating custom customer attribute

I want to make one of customer attributes not required

I run the below code, but it doesn’t work

   public function upgrade(ModuleDataSetupInterface $setup, ModuleContextInterface $context)
{
        $customerSetup = $this->customerSetupFactory->create(['setup' => $setup]);
        $customerSetup->addAttribute(
            MagentoCustomerModelCustomer::ENTITY,
            'trade_license',
            [
                'required' => false
            ]
        );
}