Fix import path of go-sdk (#141)

From code.gitea.io/go-sdk/gitea
  To code.gitea.io/sdk/gitea

vendor/code.gitea.io/sdk/gitea/repo_branch.go

@@ -0,0 +1,25 @@
+// 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 gitea
+
+import (
+	"fmt"
+)
+
+// Branch represents a repository branch.
+type Branch struct {
+	Name   string         `json:"name"`
+	Commit *PayloadCommit `json:"commit"`
+}
+
+func (c *Client) ListRepoBranches(user, repo string) ([]*Branch, error) {
+	branches := make([]*Branch, 0, 10)
+	return branches, c.getParsedResponse("GET", fmt.Sprintf("/repos/%s/%s/branches", user, repo), nil, nil, &branches)
+}
+
+func (c *Client) GetRepoBranch(user, repo, branch string) (*Branch, error) {
+	b := new(Branch)
+	return b, c.getParsedResponse("GET", fmt.Sprintf("/repos/%s/%s/branches/%s", user, repo, branch), nil, nil, &b)
+}