fix: package json

Author: ffabioteixeira

package.json

@@ -2,7 +2,7 @@
   "name": "printer-electron-node",
   "description": "Node.js and Electron bindings",
   "version": "1.7.1",
-  "main": "printer.js",
+  "main": "./lib/index.js",
   "private": false,
   "scripts": {
     "install": "node-gyp rebuild",