searchTextField button remove elevation

example/lib/example_text_field.dart

@@ -22,6 +22,7 @@ class _ExampleTextFiledState extends State<ExampleTextFiled> {
         children: [
           ASSearchTextField.button(
             hintText: '搜索',
+            onPressed: () {},
           ),
         ],
       ),

lib/text_field/as_search_text_field.dart

@@ -78,6 +78,7 @@ class _ASSearchTextFieldState extends State<ASSearchTextField> {
       child: MaterialButton(
         padding: EdgeInsets.zero,
         color: Color(0xFFF8F8F8),
+        elevation: 0,
         shape: RoundedRectangleBorder(
           borderRadius: BorderRadius.circular(21.w),
           side: BorderSide(