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/admin_org.go

@@ -0,0 +1,21 @@
+// Copyright 2015 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 (
+	"bytes"
+	"encoding/json"
+	"fmt"
+)
+
+func (c *Client) AdminCreateOrg(user string, opt CreateOrgOption) (*Organization, error) {
+	body, err := json.Marshal(&opt)
+	if err != nil {
+		return nil, err
+	}
+	org := new(Organization)
+	return org, c.getParsedResponse("POST", fmt.Sprintf("/admin/users/%s/orgs", user),
+		jsonHeader, bytes.NewReader(body), org)
+}