Fix PdfPreview default locale

 # Changelog
 
+## 5.0.0-nullsafety.1
+
+- Fix PdfPreview default locale
+
 ## 5.0.0-nullsafety.0
 
 - Remove useless files

@@ -169,8 +169,8 @@ class _PdfPreviewState extends State<PdfPreview> {
   void initState() {
     if (widget.initialPageFormat == null) {
       final locale = WidgetsBinding.instance!.window.locale;
-      // ignore: invalid_null_aware_operator
-      final cc = locale?.countryCode ?? 'US';
+      // ignore: unnecessary_cast, avoid_as
+      final cc = (locale as Locale?)?.countryCode ?? 'US';
 
       if (cc == 'US' || cc == 'CA' || cc == 'MX') {
         pageFormat = PdfPageFormat.letter;

@@ -4,7 +4,7 @@ description: Plugin that allows Flutter apps to generate and print documents to
 homepage: https://github.com/DavBfr/dart_pdf/tree/master/printing
 repository: https://github.com/DavBfr/dart_pdf
 issue_tracker: https://github.com/DavBfr/dart_pdf/issues
-version: 5.0.0-nullsafety.0
+version: 5.0.0-nullsafety.1
 
 environment:
   sdk: ">=2.12.0-0 <3.0.0"