Migrated to the null safety.

ashok-kuvaraja · ashok-kuvaraja · commit 5e755d49c447 · 2021-04-07T19:16:32.000+05:30
diff --git a/lib/main.dart b/lib/main.dart
@@ -131,7 +131,7 @@ class EmployeeDataSource extends DataGridSource {
   List<DataGridRow> get rows => _employeeData;
 
   @override
-  DataGridRowAdapter buildRow(DataGridRow row) {
+  DataGridRowAdapter? buildRow(DataGridRow row) {
     return DataGridRowAdapter(
         cells: row.getCells().map<Widget>((e) {
       return Container(
