Remove trailing comma in package file and update build dependency version

Author: tehvgg

package.json

@@ -38,7 +38,7 @@
     "@createjs/core": "2.0.0-beta.4"
   },
   "devDependencies": {
-    "@createjs/build": "2.0.0-beta.4",
+    "@createjs/build": "2.0.0-beta.5",
     "@createjs/easeljs": "2.0.0-beta.4"
   },
   "engine": "node >= 8.9.0",
@@ -56,5 +56,5 @@
     "example": "examples",
     "lib": "dist",
     "test": "tests"
-  },
+  }
 }