chore: upgrade example to Dart >=3.5.0

example/main.dart

diff --git a/example/main.dart b/example/main.dart
index 9522de4..0b06a7a 100644
--- a/example/main.dart
+++ b/example/main.dart
@@ -17,15 +17,15 @@
 
 class EquatableDateTime extends DateTime with EquatableMixin {
   EquatableDateTime(
-    int year, [
-    int month = 1,
-    int day = 1,
-    int hour = 0,
-    int minute = 0,
-    int second = 0,
-    int millisecond = 0,
-    int microsecond = 0,
-  ]) : super(year, month, day, hour, minute, second, millisecond, microsecond);
+    super.year, [
+    super.month,
+    super.day,
+    super.hour,
+    super.minute,
+    super.second,
+    super.millisecond,
+    super.microsecond,
+  ]);
 
   @override
   List<Object> get props {

example/pubspec.yaml

diff --git a/example/pubspec.yaml b/example/pubspec.yaml
index de237dd..667d7c6 100644
--- a/example/pubspec.yaml
+++ b/example/pubspec.yaml
@@ -1,7 +1,7 @@
 name: example
 
 environment:
-  sdk: ">=2.12.0 <3.0.0"
+  sdk: ">=3.5.0 <4.0.0"
 
 dependencies:
   equatable: