Laravel 9 Update (#1413)

Update to Laravel 9 and PHP 8+

Co-authored-by: B.Fatih KOZ <fatih.koz@gmail.com>

app/Services/ImportExport/FlightExporter.php

@@ -36,7 +36,7 @@ class FlightExporter extends ImportExport
         }
 
         // Modify special fields
-        $ret['airline'] = $ret['airline']->icao;
+        $ret['airline'] = $flight->airline->icao;
         $ret['dpt_airport'] = $flight->dpt_airport_id;
         $ret['arr_airport'] = $flight->arr_airport_id;