add prepack script

package.json

@@ -9,12 +9,13 @@
     "url": "https://zeteo.me/gitea/Outils-PeerTube/listener-rss-agregators/issues"
   },
   "files": [
-    "build/"
+    "build/",
+    "README.md",
+    "package.json"
   ],
   "scripts": {
     "test": "cross-env TS_NODE_PROJECT='./tests/tsconfig.json' mocha --require ts-node/register ./tests/**/*-spec.ts",
-    "build": "tsc",
-    "postinstall": "npm run build"
+    "build": "ls . && tsc -p ."
   },
   "keywords": [
     "RSS",