added moment.js as dependency because it was removed in react-datepicker

static/package.json

@@ -13,6 +13,7 @@
     }
   },
   "dependencies": {
+    "moment": "^2.20.0",
     "prismjs": "1.9.0",
     "react": "16.2.0",
     "react-clipboard.js": "1.1.3",
@@ -35,4 +36,4 @@
     "test": "react-scripts test --env=jsdom",
     "eject": "react-scripts eject"
   }
-}
+}