Fix: unused import and Ping router return wrong version

routers/controllers/site.go

@@ -49,7 +49,7 @@ func Ping(c *gin.Context) {
 
 	c.JSON(200, serializer.Response{
 		Code: 0,
-		Data: conf.BackendVersion + conf.IsPro,
+		Data: version,
 	})
 }
 

routers/controllers/slave.go

@@ -2,8 +2,6 @@ package controllers
 
 import (
 	"context"
-	"net/url"
-	"strconv"
 
 	"github.com/cloudreve/Cloudreve/v3/pkg/request"
 	"github.com/cloudreve/Cloudreve/v3/pkg/serializer"