add timezone and timeformat (#572)

* add timezone and timeformat

* rm time zone and keep time format

Co-authored-by: Tony Wang <tonywang.data@gmail.com>

core/logx/config.go

@@ -4,6 +4,7 @@ package logx
 type LogConf struct {
 	ServiceName         string `json:",optional"`
 	Mode                string `json:",default=console,options=console|file|volume"`
+	TimeFormat          string `json:",optional"`
 	Path                string `json:",default=logs"`
 	Level               string `json:",default=info,options=info|error|severe"`
 	Compress            bool   `json:",optional"`