circleci.go
func (c *Client) ListEnvVars(account, repo string) ([]EnvVar, error) {
	envVar := []EnvVar{}

	err := c.request("GET", fmt.Sprintf("project/%s/%s/envvar", account, repo), &envVar, nil, nil)
	if err != nil {
		return nil, err
	}

	return envVar, nil
}
func (c *Client) ListEnvVars(account, repo string) ([]EnvVar, error) {
	envVar := []EnvVar{}

	err := c.request("GET", fmt.Sprintf("project/%s/%s/envvar", account, repo), &envVar, nil, nil)
	if err != nil {
		return nil, err
	}

	return envVar, nil
}
// ListEnvVars list environment variable to the specified project
// Returns the env vars (the value will be masked)