api:doc command not working

| Q | A
| ----------------- | ---
| Bug? | yes
| New Feature? | no
| Framework | Laravel
| Framework version | 5.8.35
| Package version | 2.3.0
| PHP version | 7.3.8

#### Actual Behaviour

With followed docblock
```php
/**
* Login user
*
* Login user with a `username` and `password`
*
* @Post("/auth/login")
*/
public function login(Request $request)
```
there is exception in `api:doc` command

```

InvalidArgumentException : Expected a string. Got: boolean

at vendor/webmozart/assert/src/Assert.php:1696
1692| * @param string $message
1693| */
1694| protected static function reportInvalidArgument($message)
1695| {
> 1696| throw new InvalidArgumentException($message);
1697| }
1698|
1699| private function __construct()
1700| {

Exception trace:

1 Webmozart\Assert\Assert::reportInvalidArgument("Expected a string. Got: boolean")
vendor/webmozart/assert/src/Assert.php:206

2 Webmozart\Assert\Assert::string("")
vendor/webmozart/assert/src/Assert.php:219

3 Webmozart\Assert\Assert::stringNotEmpty()
vendor/phpdocumentor/reflection-docblock/src/DocBlockFactory.php:84

4 phpDocumentor\Reflection\DocBlockFactory::create()
vendor/dingo/blueprint/src/RestResource.php:144

5 Dingo\Blueprint\RestResource::getDescription()
vendor/dingo/blueprint/src/Blueprint.php:148
...
```