Cannot read the targetfile when I placed the config file in a subpakage and then run program with Environment argument

[surandor]

code like:
configPath := flag.String("conf", "config/config.yml", "default config file name ： config.yml")
env := flag.String("env", "", "run environment： default： test, opt: prod / dev")
flag.Parse()
configor.New(&configor.Config{Environment: *env}).Load(&Config, *configPath)

the run command is :
go build -o main.exe main.go
main.exe -conf ./config/config.yml -env prod

but the program load the file named config.yml not config.prod.yml