Upgrading package.json

With reference to fix: remove ReDoS regexp(debug-js/debug#504)

Author: stenalpjolly

package.json

@@ -34,7 +34,7 @@
     "content-type": "~1.0.4",
     "cookie": "0.3.1",
     "cookie-signature": "1.0.6",
-    "debug": "2.6.9",
+    "debug": "3.1.0",
     "depd": "~1.1.2",
     "encodeurl": "~1.0.2",
     "escape-html": "~1.0.3",