update version

Author: jojoliang

cos.go

@@ -22,7 +22,7 @@ import (
 
 const (
 	// Version current go sdk version
-	Version               = "0.7.28"
+	Version               = "0.7.29"
 	userAgent             = "cos-go-sdk-v5/" + Version
 	contentTypeXML        = "application/xml"
 	defaultServiceBaseURL = "http://service.cos.myqcloud.com"