Playback rate (#411)

* update

packages/artplayer/src/player/playbackRateMix.js

@@ -1,4 +1,4 @@
-import { errorHandle, def } from '../utils';
+import { def } from '../utils';
 
 export default function playbackRateMix(art) {
     const {
@@ -14,8 +14,6 @@ export default function playbackRateMix(art) {
         set(rate) {
             if (rate) {
                 if (rate === $video.playbackRate) return;
-                const rateList = [0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 1.75, 2.0, 3.0, 4.0];
-                errorHandle(rateList.includes(rate), `'playbackRate' only accept ${rateList.toString()} as parameters`);
                 $video.playbackRate = rate;
                 notice.show = `${i18n.get('Rate')}: ${rate === 1.0 ? i18n.get('Normal') : `${rate}x`}`;
                 art.emit('playbackRate', rate);