Merge branch '2-add-optional-prefix-for-env-variables' into 'main'

fix typescript definition

Closes #2

See merge request !3

index.d.ts

-export as namespace Config;
-
-export = Config;
-
-declare class Config {
+export class Config {
     constructor();
     _reload(): void;
     _show(): any;

package.json

 {
   "name": "@libs/config",
-  "version": "1.13.0",
+  "version": "1.13.1",
   "description": "Simple Config with ENV Support",
   "main": "index.js",
   "scripts": {