update docs

test/types.test.ts

@@ -1,6 +1,11 @@
 import Artplayer from '../packages/artplayer';
+import { type Option } from '../packages/artplayer/types/option';
 
-const art = new Artplayer({
+const option: Option = {
     container: '.artplayer-app',
     url: './assets/sample/video.mp4',
-});
+};
+
+option.volume = 0.5;
+
+const art = new Artplayer(option);