bump loader-builder to 2.4.1

Author: alsotang

package.json

@@ -25,7 +25,7 @@
     "helmet": "1.3.0",
     "ioredis": "1.15.1",
     "jpush-sdk": "3.2.1",
-    "loader-builder": "2.1.0",
+    "loader-builder": "2.4.1",
     "loader": "2.1.1",
     "lodash": "4.16.2",
     "log4js": "^0.6.29",