fix: add missing parsing of participants' nationality

src/BusProNet/XmlParser/BookingParser.php

@@ -120,6 +120,7 @@ class BookingParser extends AbstractParser
         $personalData->title = $this->getStringOrNullValue($node->filterXPath('//titel'));
         $genderValue = $this->getStringOrNullValue($node->filterXPath('//geschlecht'));
         $personalData->gender = null !== $genderValue ? strtoupper($genderValue) : null;
+        $personalData->nationality = $this->getStringOrNullValue($node->filterXPath('//nationalitaet'));
 
         $personalData->height = $this->getStringOrNullValue($node->filterXPath('//sonstiges1'));
         $personalData->weight = $this->getStringOrNullValue($node->filterXPath('//sonstiges2'));