fix(type): put policy persistent type

Author: lihsai0

index.d.ts

@@ -1779,7 +1779,7 @@ export declare namespace rs {
         persistentOps?: string;
         persistentNotifyUrl?: string;
         persistentPipeline?: string;
-        persistentType?: string;
+        persistentType?: number;
 
         fsizeLimit?: number;
         fsizeMin?: number;

qiniu/storage/rs.js

@@ -1695,7 +1695,7 @@ function _putPolicyBuildInKeys () {
  * @property {string} [persistentOps]
  * @property {string} [persistentNotifyUrl]
  * @property {string} [persistentPipeline]
- * @property {string} [persistentType]
+ * @property {number} [persistentType]
  * @property {number} [fsizeLimit]
  * @property {number} [fsizeMin]
  * @property {string} [mimeLimit]