feature：修改壁纸延迟30ms传一次

pages/piano/cropper/cropper.js

@@ -448,7 +448,7 @@ Page({
       _this.updateProgress(next, total);
 
       i++;
-    }, 5);
+    }, 30);
   },
   async delay(ms) {
     return new Promise(resolve => setTimeout(resolve, ms));