add: version cmd

add: dockerfile

main.go

@@ -5,6 +5,13 @@ import (
 	"sub2sing-box/cmd"
 )
 
+var Version string
+
+func init() {
+	Version = "dev"
+	cmd.SetVersion(Version)
+}
+
 func main() {
 	if err := cmd.RootCmd.Execute(); err != nil {
 		fmt.Println(err)