config does not use ParseEnv option on nested keys.

[Linken Quy Dinh]

System (please complete the following information):

• OS: linux
• GO Version: 1.16.4
• Pkg Version: 2.0.23

Describe the bug

config does not use ParseEnv option on nested keys.

To Reproduce

import (
    config "github.com/gookit/config/v2"
)

func BugReport() {
	jsonStr := `{
    "envKey": "${SHELL}",
    "map1": {
        "key1": "${SHELL}"
    }
}`

	config.AddDriver(config.JSONDriver)
	config.WithOptions(config.ParseEnv)
	_ = config.LoadStrings(config.JSON, jsonStr)
	// works ok /bin/my-shell
	fmt.Println(config.String("envKey", ""))
	map1 := config.StringMap("map1")
	// "${SHELL}"
	fmt.Println("get map", map1["key1"])
}

Expected behavior
should give me /bin/bash

fmt.Println("get map", map1["key1"])

[Linken Quy Dinh]

@inhere you have to make a new release.

[Inhere]

has been released, thanks :)