added validation and ui changes in add task ui

Author: Pavel401

lib/views/home/home.dart

@@ -10,7 +10,7 @@ import 'package:taskwarrior/config/app_settings.dart';
 import 'package:taskwarrior/drawer/filter_drawer.dart';
 import 'package:taskwarrior/drawer/nav_drawer.dart';
 import 'package:taskwarrior/model/storage/storage_widget.dart';
-import 'package:taskwarrior/widgets/addTask.dart';
+import 'package:taskwarrior/widgets/add_Task.dart';
 import 'package:taskwarrior/widgets/buildTasks.dart';
 import 'package:taskwarrior/widgets/pallete.dart';
 import 'package:taskwarrior/widgets/tag_filter.dart';