[Inflector] Wrong plural inflection of word 'season'

**Symfony version(s) affected**: 4.3

**Description**  
When you call `Symfony\Component\Inflector\Inflector::pluralize('season')` it returns `seasa` instead of `seasons`.

**How to reproduce**  
```php
<?php
use Symfony\Component\Inflector\Inflector;

var_dump(Inflector::pluralize('season')); // seasa
```