fix(uploader): remove wx:key="*this"

Author: Tidyzq

src/uploader/uploader.wxml

@@ -10,7 +10,7 @@
     </view>
     <view class="weui-uploader__bd">
         <view class="weui-uploader__files">
-            <block wx:for="{{currentFiles}}" wx:key="*this">
+            <block wx:for="{{currentFiles}}">
                 <view wx:if="{{item.error}}" data-index="{{index}}" bindtap="previewImage" class="weui-uploader__file weui-uploader__file_status">
                     <image class="weui-uploader__img" src="{{item.url}}" mode="aspectFill" />
                     <view class="weui-uploader__file-content">