[Finder] Add GLOB_BRACE support in Finder::in() method

**before**

```php
$finder->files()->in([
    'My/First/Directory',
    'My/Second/Directory',
    'My/Third/Directory',
]);
```

**after**

```php
$finder->files()->in('My/{First,Second,Third}/Directory');
```

---

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | ~
| License       | MIT
| Doc PR        | ~