feat(harmony): 支付页面添加邮件

pages/API/request-payment/request-payment.uvue

 <template>
-  <page-head title="发起支付"></page-head>
-
+  <page-head title="发起支付"></page-head>
+  <view class="uni-common-mt" style="padding: 0 10px;">
+    <text>如对当前页面的支付示例功能有任何疑问，通过电子邮件：service@dcloud.io 联系我们</text>
+  </view>
   <template v-if="providerList.length > 0">
     <button style="margin-top: 20px;" type="primary" v-for="(item,index) in providerList" :key="index"
       @click="requestPayment(item)">{{item.name}}</button>

pages/API/request-payment/request-payment/request-payment-uni-pay.uvue

 <template>
   <view class="app">
+    <view class="uni-common-mb">
+      <text>如对当前页面的支付示例功能有任何疑问，通过电子邮件：service@dcloud.io 联系我们</text>
+    </view>
     <view v-if="errMsg != ''">
       <text class="err-msg">注意：{{ errMsg }}</text>
     </view>