chore: ✏️ fix typo in description

Author: lehuygiang28

package.json

@@ -5,7 +5,7 @@
         "url": "git+https://github.com/lehuygiang28/vnpay.git"
     },
     "version": "0.6.0",
-    "description": "A open-source library support to payment with VNPay",
+    "description": "An open-source nodejs library support to payment with VNPay",
     "main": "lib/index.js",
     "types": "lib/index.d.ts",
     "files": [