😒 chore(package.json): Set files key.

Author: make-github-pseudonymous-again

package.json

@@ -43,6 +43,9 @@
     "esdoc": "1.1.0",
     "nyc": "15.0.1"
   },
+  "files": [
+    "lib"
+  ],
   "homepage": "http://aureooms.github.io/js-binomial-heap/",
   "keywords": [
     "binomial",