Fix null PlatformFIle.extension error when called on Web

CHANGELOG.md

@@ -1,3 +1,6 @@
+## 2.0.13
+Updates `extension` helper getter to use the `name` property instead of `path`, since the latest isn't available on the Web, hence, the extension wouldn't be as well. Thank you @markgrancapal.
+
 ## 2.0.12
 Android:
 

lib/src/platform_file.dart

@@ -32,5 +32,5 @@ class PlatformFile {
   final int size;
 
   /// File extension for this file.
-  String get extension => path?.split('.')?.last;
+  String get extension => name?.split('.')?.last;
 }

pubspec.yaml

@@ -1,7 +1,7 @@
 name: file_picker
 description: A package that allows you to use a native file explorer to pick single or multiple absolute file paths, with extension filtering support.
 homepage: https://github.com/miguelpruivo/plugins_flutter_file_picker
-version: 2.0.12
+version: 2.0.13
 
 dependencies:
   flutter: