build(npm): add package.json to exports

Author: Eduard Aksamitov

package.json

@@ -20,7 +20,8 @@
   "type": "module",
   "types": "./index.d.ts",
   "exports": {
-    ".": "./index.js"
+    ".": "./index.js",
+    "./package.json": "./package.json"
   },
   "engines": {
     "node": "^12.0.0 || ^14.0.0 || >=16.0.0"