bug fix

src/pages/channel/edit.jsx

         value: newsData.channelImg,
         rules: [
             { required: true, message: '请选择公司logo' },
-          ]
+          ],
+        help: '用于渠道代理平台导航logo(建议尺寸42*42px)',
       },
       {
         label: '联系人',
         type: FieldTypes.Text,
         rules: [
           {required: true, message: '请输入联系人'},
+          { max: 30, message: '联系人不超过30个字符' }
         ]
       },
       {