Exclude unnecessary files from npm module

Author: krismuniz

package.json

@@ -12,6 +12,10 @@
     "test": "nyc --reporter=html --reporter=text mocha",
     "lint": "eslint ."
   },
+  "files": [
+    "*.d.ts",
+    "lib"
+  ],
   "runkitExample": "const transformJS = require('js-to-json-logic');",
   "keywords": [
     "json",