Move sdk structs to modules/structs (#6905)

* move sdk structs to moduels/structs

* fix tests

* fix fmt

* fix swagger

* fix vendor

modules/structs/issue_label.go

@@ -0,0 +1,36 @@
+// Copyright 2016 The Gogs 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 structs
+
+// Label a label to an issue or a pr
+// swagger:model
+type Label struct {
+	ID   int64  `json:"id"`
+	Name string `json:"name"`
+	// example: 00aabb
+	Color string `json:"color"`
+	URL   string `json:"url"`
+}
+
+// CreateLabelOption options for creating a label
+type CreateLabelOption struct {
+	// required:true
+	Name string `json:"name" binding:"Required"`
+	// required:true
+	// example: #00aabb
+	Color string `json:"color" binding:"Required;Size(7)"`
+}
+
+// EditLabelOption options for editing a label
+type EditLabelOption struct {
+	Name  *string `json:"name"`
+	Color *string `json:"color"`
+}
+
+// IssueLabelsOption a collection of labels
+type IssueLabelsOption struct {
+	// list of label IDs
+	Labels []int64 `json:"labels"`
+}