Move issue change status from models to service (#8691)

services/issue/status.go

@@ -0,0 +1,21 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package issue
+
+import (
+	"code.gitea.io/gitea/models"
+	"code.gitea.io/gitea/modules/notification"
+)
+
+// ChangeStatus changes issue status to open or closed.
+func ChangeStatus(issue *models.Issue, doer *models.User, isClosed bool) (err error) {
+	err = issue.ChangeStatus(doer, isClosed)
+	if err != nil {
+		return
+	}
+
+	notification.NotifyIssueChangeStatus(doer, issue, isClosed)
+	return nil
+}