Update Slovenia.php (#235)

Wrong date fixed. It's 8th of February

src/Countries/Slovenia.php

@@ -17,7 +17,7 @@ protected function allHolidays(int $year): array
         return array_merge([
             'Novo leto' => '01-01', // New Year's Day
             'Novo leto 2' => '01-02', // New Year's Day, yes it's a second day
-            'Prešernov dan, slovenski kulturni praznik' => '08-02', // Prešeren Day, Slovenian Cultural Holiday
+            'Prešernov dan, slovenski kulturni praznik' => '02-08', // Prešeren Day, Slovenian Cultural Holiday
             'Dan upora proti okupatorju' => '04-27', // Day of Uprising Against Occupation
             'Praznik dela' => '05-01',  // Labour Day
             'Praznik dela 2' => '05-02', // Labour Day, yes it's a second day