Update gitea go-sdk to v0.15.0 (#385)

Update "code.gitea.io/sdk/gitea" to latest release

Reviewed-on: https://gitea.com/gitea/tea/pulls/385
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Reviewed-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: 6543 <6543@obermui.de>
Co-committed-by: 6543 <6543@obermui.de>

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

@@ -26,6 +26,9 @@ func (c *Client) AdminListOrgs(opt AdminListOrgsOptions) ([]*Organization, *Resp
 
 // AdminCreateOrg create an organization
 func (c *Client) AdminCreateOrg(user string, opt CreateOrgOption) (*Organization, *Response, error) {
+	if err := escapeValidatePathSegments(&user); err != nil {
+		return nil, nil, err
+	}
 	body, err := json.Marshal(&opt)
 	if err != nil {
 		return nil, nil, err