chore(package): explicitly declare js module type (#166)

Author: Fdawgs

package.json

@@ -3,6 +3,7 @@
   "version": "5.2.2",
   "description": "Fastify PostgreSQL connection plugin",
   "main": "index.js",
+  "type": "commonjs",
   "types": "index.d.ts",
   "scripts": {
     "check-examples": "tsc --build examples/typescript/*",