[Go-server] Fix formatting of go-server generated code (#7162)

* Add missing go-server petstore batch script

* Make go-server confirm to gofmt

samples/server/petstore/go-api-server/main.go

@@ -1,6 +1,9 @@
 package main
 
 import (
+	"log"
+	"net/http"
+
 	// WARNING!
 	// Change this to a fully-qualified import path
 	// once you place this file into your project.
@@ -9,14 +12,12 @@ import (
 	//    sw "github.com/myname/myrepo/go"
 	//
 	sw "./go"
-	"log"
-	"net/http"
 )
 
 func main() {
 	log.Printf("Server started")
 
 	router := sw.NewRouter()
-	
+
 	log.Fatal(http.ListenAndServe(":8080", router))
 }