Update package.json

Author: johnnyreilly

Diff for: packages/react-scripts/package.json

@@ -50,7 +50,7 @@
     "tslint": "^5.8.0",
     "tslint-react": "^3.2.0",
     "typescript": "~2.6.1",
-    "source-map-loader": "^0.2.3"
+    "source-map-loader": "^0.2.3",
     "sw-precache-webpack-plugin": "0.11.4",
     "url-loader": "0.6.2",
     "webpack": "3.8.1",