fix wechat token from cache option

client.go

@@ -23,8 +23,8 @@ func NewClient(appID, appSecret, token, encodingAESKey string) *Client {
 }
 
 // UseCacheToken token from cache
-func (wc *Client) UseCacheToken() {
-	wc.UseCacheToken = true
+func (wc *Client) UseCacheToken(ok bool) {
+	wc.UseCacheToken = ok
 }
 
 // getToken get token