Elment-plus表单验证规则，不生效解决办法

以官网代码为例

<template>
  <el-form
    ref="ruleFormRef"
    style="max-width: 600px"
    :model="ruleForm"
    :rules="rules"
    label-width="auto"
    class="demo-ruleForm"
    :size="formSize"
    status-icon
  >
    <el-form-item label="Activity name" prop="name">
      <el-input v-model="ruleForm.name" />
    </el-form-item>
    <el-form-item label="Activity zone" prop="region">
      <el-select v-model="ruleForm.region" placeholder="Activity zone">
        <el-option label="Zone one" value="shanghai" />
        <el-option label="Zone two" value="beijing" />
      </el-select>
    </el-form-item>
    <el-form-item label="Activity count" prop="count">
      <el-select-v2
        v-model="ruleForm.count"
        placeholder="Activity count"
        :options="options"
      />
    </el-form-item>
    <el-form-item label="Activity time" required>
      <el-col :span="11">
        <el-form-item prop="date1">
          <el-date-picker
            v-model="ruleForm.date1"
            type="date"
            aria-label="Pick a date"
            placeholder="Pick a date"
            style="width: 100%"
          />
        </el-form-item>
      </el-col>
      <el-col class="text-center" :span="2">
        <span class="text-gray-500">-</span>
      </el-col>
      <el-col :span=