feat(ESModules): importing for esm modules (#3998)

* fix: importing for esm modules

* style: use single quotes

* refactor: remove 'use strict'

package.json

@@ -4,6 +4,16 @@
   "description": "A powerful library for interacting with the Discord API",
   "main": "./src/index",
   "types": "./typings/index.d.ts",
+  "exports": {
+    ".": [
+      {
+        "require": "./src/index.js",
+        "import": "./esm/discord.mjs"
+      },
+      "./src/index.js"
+    ],
+    "./esm": "./esm/discord.mjs"
+  },
   "scripts": {
     "test": "npm run lint && npm run docs:test && npm run lint:typings",
     "test:typescript": "tsc",