How to display action button as dropdown in Yii2 gridview?

I would like to display action button as dropdown in Yii 2 gridview. How can I achieve that without using any extension?

I have added the source code bellow-


<?= GridView::widget([

	'dataProvider' => $dataProvider,

	'filterModel' => $searchModel,

	'columns' => [

			['class' => 'yii\grid\SerialColumn'],


			'id',

			'name',


			['class' => 'yii\grid\ActionColumn',

					'template'=>'{view}{update}{delete}',

					'buttons' => [

							'view' => function ($url, $model) {

									return Html::a('<span class="glyphicon glyphicon-eye-open"></span>', $url, [

											'title' => Yii::t('app', 'View'),

									]);

							},

							'update' => function ($url, $model) {

									return Html::a('<span class="glyphicon glyphicon-pencil"></span>', $url, [

											'title' => Yii::t('app', 'Update'),

									]);

							},

					],


					'urlCreator' => function ($action, $model, $key, $index) {

							if ($action === 'view') {

									$url ='/site/view?id='.$model->id;

									return $url;

							}

							if ($action === 'update') {

									$url ='/site/update?id='.$model->id;

									return $url;

							}

					}

			],

	],

]); ?>