Fix error log when loading issues caused by a xorm bug (#7271)

* fix error log when loading issues caused by a xorm bug

* upgrade packages

* fix fmt

* fix Consistency

* fix tests

models/repo_unit.go

@@ -10,8 +10,8 @@ import (
 	"code.gitea.io/gitea/modules/util"
 
 	"github.com/Unknwon/com"
-	"github.com/go-xorm/core"
 	"github.com/go-xorm/xorm"
+	"xorm.io/core"
 )
 
 // RepoUnit describes all units of a repository