Upgrade React-scripts & add npm lock

package.json

@@ -18,7 +18,7 @@
     "react-dom": "^16.7.0",
     "react-jsonschema-form": "^1.5.0",
     "react-numeric-input": "^2.2.3",
-    "react-scripts": "^2.1.8",
+    "react-scripts": "^3.0.1",
     "react-sizeme": "^2.5.2",
     "roslib": "^1.0.1"
   },