fix: chmod before publishing

Author: aminya

package.json

@@ -18,12 +18,14 @@
   },
   "scripts": {
     "test": "mocha test && standard",
+    "prepublishOnly": "shx chmod -R +x ./bin",
     "preinstall": "node build.js"
   },
   "devDependencies": {
     "electron-download": "^3.0.1",
     "extract-zip": "^1.5.0",
     "mocha": "^3.1.2",
+    "shx": "^0.3.3",
     "standard": "^8.4.0",
     "temp": "^0.8.3"
   },