fix(carousel) 走马灯手动轮播切换到此处数据会偶现与实际不符 (#188)

examples/docs/resources/pc/demo/carousel/manual-play.vue

@@ -1,6 +1,6 @@
 <template>
   <div>
-    <tiny-carousel height="150px" ref="carousel" :initial-index="index - 1">
+    <tiny-carousel height="150px" ref="carousel" :initial-index="index - 1" @change="handleChange">
       <tiny-carousel-item class="carousel-item-demo" v-for="item in 8" :key="item" :name="'幻灯片 - ' + item">
         <h3>{{ item }}</h3>
       </tiny-carousel-item>
@@ -43,6 +43,11 @@ export default {
     prev() {
       this.index = Math.max(this.index - 1, 0)
       this.$refs.carousel.prev()
+    },
+    handleChange(newVal) {
+      if (newVal >= 0) {
+        this.index = newVal + 1
+      }
     }
   }
 }