如何在Yii2网格视图中全局更改ActionColumn图标？

'gridview' => [
    'class' => 'yii\grid\GridView',
    'columns' => [
        // other columns...

        [
            'class' => 'yii\grid\ActionColumn',
            'template' => '{view} {update} {delete}',
            'buttons' => [
                'view' => function ($url, $model, $key) {
                    return Html::a('<i class="fa fa-eye"></i>', $url, ['title' => 'View']);
                },
                'update' => function ($url, $model, $key) {
                    return Html::a('<i class="fa fa-pencil"></i>', $url, ['title' => 'Update']);
                },
                'delete' => function ($url, $model, $key) {
                    return Html::a('<i class="fa fa-trash"></i>', $url, ['title' => 'Delete']);
                },
            ],
        ],
    ],
],