iview2.0 InputNumber 保留两位小数

<FormItem prop="free" label="包期费用(元)：">
          <Input-number
            :min="0"
            style="width: 100%"
            v-model="formValidate.free"
            placeholder="请输入单价(元)"
            :formatter="value => `${parseFloat(Math.floor(value*100)/100)}`"
          />
        </FormItem>