plugins: mark entrypoint as index

packages/elastic/package.json

@@ -1,7 +1,7 @@
 {
     "name": "@hydrooj/elastic-search",
     "version": "1.0.8",
-    "main": "package.json",
+    "main": "index.ts",
     "repository": "https://github.com/hydro-dev/Hydro",
     "author": "undefined <i@undefined.moe>",
     "license": "AGPL-3.0-or-later",