修复从 token 解析 bucket 的 bug & 完善下类型 & fix issue

package.json

@@ -1,7 +1,7 @@
 {
   "name": "qiniu-js",
   "jsName": "qiniu",
-  "version": "3.0.2",
+  "version": "3.0.3",
   "private": false,
   "description": "Javascript SDK for Qiniu Resource (Cloud) Storage AP",
   "main": "lib/index.js",

src/upload/base.ts

@@ -126,8 +126,11 @@ export default abstract class Base {
     this.onData = handlers.onData
     this.onError = handlers.onError
     this.onComplete = handlers.onComplete
-
-    this.bucket = utils.getPutPolicy(this.token).bucket
+    try {
+      this.bucket = utils.getPutPolicy(this.token).bucket
+    } catch (e) {
+      this.onError(e)
+    }
   }
 
   public async putFile(): Promise<utils.ResponseSuccess<UploadCompleteData>> {

src/utils.ts

@@ -273,7 +273,7 @@ interface PutPolicy {
 export function getPutPolicy(token: string) {
   const segments = token.split(':')
   const ak = segments[0]
-  const putPolicy: PutPolicy = JSON.parse(urlSafeBase64Decode(segments[2]))
+  const putPolicy: PutPolicy = JSON.parse(urlSafeBase64Decode(segments[segments.length - 1]))
 
   return {
     ak,