Save `nyc` as a devDependency

package.json

@@ -128,6 +128,7 @@
     "node-sass": "^4.5.0",
     "npm-run-all": "4.0.2",
     "null-loader": "0.1.1",
+    "nyc": "^11.3.0",
     "open": "0.0.5",
     "postcss-loader": "2.0.6",
     "raw-loader": "0.5.1",
@@ -156,6 +157,8 @@
   },
   "nyc": {
     "all": true,
-    "include": ["**/src/core/plugins/**.js"]
+    "include": [
+      "**/src/core/plugins/**.js"
+    ]
   }
 }