npm whitelist index vs ignore other files

Author: jonathantneal

.npmignore

@@ -16,6 +16,9 @@
     "url": "https://github.com/MattDiMu/postcss-replace-overflow-wrap/issues"
   },
   "homepage": "https://github.com/MattDiMu/postcss-replace-overflow-wrap",
+  "files": [
+    "index.js"
+  ],
   "dependencies": {
     "postcss": "^6.0.1"
   },