package.json: fix main

package.json

@@ -2,7 +2,7 @@
   "name": "amd-config-builder",
   "version": "0.1.0",
   "description": "Builds amd config for a project from configs of its components",
-  "main": "lib/configbuilder.js",
+  "main": "lib/config-builder.js",
   "scripts": {
     "test": "mocha"
   },