Fix "mutable-buffer" version.

Author: WillianGoncalves

package.json

@@ -37,7 +37,7 @@
     "handlebars": "^4.0.10",
     "lodash": "^4.17.4",
     "moment": "^2.18.1",
-    "mutable-buffer": "^2.0.3",
+    "mutable-buffer": "2.0.3",
     "numeral": "^2.0.6",
     "xml-parser": "^1.2.1"
   },