chore(package): update dateformat to version 3.0.3

Author: greenkeeper[bot]

package.json

@@ -25,7 +25,7 @@
     "@types/form-data": "^2.2.1",
     "@types/mocha": "^2.2.45",
     "codecov": "3.0.0",
-    "dateformat": "3.0.2",
+    "dateformat": "3.0.3",
     "execa": "0.9.0",
     "fetch-mock": "5.13.1",
     "http-server": "0.11.1",