Add gh-pages back as a devDependency

Author: BrianMitchL

package-lock.json

@@ -39,6 +39,7 @@
     "format": "prettier --write \"src/**/*.{js,json,css}\""
   },
   "devDependencies": {
+    "gh-pages": "^2.0.1",
     "husky": "^1.1.3",
     "lint-staged": "^8.0.4",
     "prettier": "^1.14.3"