prow/github/client.go
func (c *Client) UpdateRepoLabel(org, repo, label, newName, description, color string) error {
	c.log("UpdateRepoLabel", org, repo, label, newName, color)
	_, err := c.request(&request{
		method:      http.MethodPatch,
		path:        fmt.Sprintf("/repos/%s/%s/labels/%s", org, repo, label),
		accept:      "application/vnd.github.symmetra-preview+json", // allow the description field -- https://developer.github.com/changes/2018-02-22-label-description-search-preview/
		requestBody: Label{Name: newName, Description: description, Color: color},
		exitCodes:   []int{200},
	}, nil)
	return err
}
func (c *Client) UpdateRepoLabel(org, repo, label, newName, description, color string) error {
	c.log("UpdateRepoLabel", org, repo, label, newName, color)
	_, err := c.request(&request{
		method:      http.MethodPatch,
		path:        fmt.Sprintf("/repos/%s/%s/labels/%s", org, repo, label),
		accept:      "application/vnd.github.symmetra-preview+json", // allow the description field -- https://developer.github.com/changes/2018-02-22-label-description-search-preview/
		requestBody: Label{Name: newName, Description: description, Color: color},
		exitCodes:   []int{200},
	}, nil)
	return err
}
// UpdateRepoLabel updates a org/repo label to new name, description, and color
//
// See https://developer.github.com/v3/issues/labels/#update-a-label