Update sdk version

CoderJava · CoderJava · commit aa6a87648049 · 2023-07-13T11:30:07.000+07:00
diff --git a/pubspec.yaml b/pubspec.yaml
@@ -4,7 +4,7 @@ version: 1.2.1
 repository: https://github.com/nusanet/flutter-treeview-plus
 
 environment:
-  sdk: '>=2.19.0 <3.0.0'
+  sdk: '>=2.19.0 <4.0.0'
   flutter: ">=1.17.0"
 
 dependencies:
