app.json
"useExtendedLib": {
  "weui": true
}

index.json
"usingComponents": {
  "mp-checkbox": "weui-miniprogram/checkbox/checkbox",
  "mp-checkbox-group": "weui-miniprogram/checkbox-group/checkbox-group"
}

index.wxml
<mp-checkbox-group multi="{{false}}">
  <mp-checkbox ext-class="custom-fault-checkbox" label="{{item}}" value="{{item}}" wx:for="{{10}}" wx:key="index" />
</mp-checkbox-group>  

基础库：2.20.3