更新README

README.md

 ```javascript
 ```javascript
 /// 选择图片
 /// 选择图片
 /// 返回格式为
 /// 返回格式为
-/// { uri: '', base64: '' }
+/// [{ uri: '', base64: '' }, { uri: '', base64: '' }, ...]
 async function pickerPhoto() {
 async function pickerPhoto() {
     try {
     try {
-        const res = await jssdk.pickerPhoto();
+        // 参数为允许选择图片数量(最多允许选择9张图片)
+        const res = await jssdk.pickerPhoto(1);
         document.getElementById('img').src = res.base64;
         document.getElementById('img').src = res.base64;
     } catch (error) {
     } catch (error) {
         console.error(error);
         console.error(error);
@@ -28,6 +29,7 @@ async function takePhotos() {
 /// { uri: '', base64: '' }
 /// { uri: '', base64: '' }
 async function startRecordAudio() {
 async function startRecordAudio() {
     try {
     try {
+        // 参数为最长录音限制时间(单位: 秒，最大2分钟)
         const res = await jssdk.startRecordAudio(30);
         const res = await jssdk.startRecordAudio(30);
         alert(res);
         alert(res);
         document.getElementById('audio').src = res.base64;
         document.getElementById('audio').src = res.base64;