config.go
func LoadWithEnvJSON(conf interface{}, configPaths ...string) error {
	return loadWithFunc(conf, configPaths, envReplacer, json.Unmarshal)
}
func LoadWithEnvJSON(conf interface{}, configPaths ...string) error {
	return loadWithFunc(conf, configPaths, envReplacer, json.Unmarshal)
}
// LoadWithEnvJSON loads JSON files with Env