chore(package): update hawk to version 5.1.2

https://greenkeeper.io/

package.json

@@ -31,7 +31,7 @@
     "forever-agent": "~0.6.1",
     "form-data": "~1.0.0-rc4",
     "har-validator": "~2.0.6",
-    "hawk": "~3.1.3",
+    "hawk": "~5.1.2",
     "http-signature": "~1.1.0",
     "is-typedarray": "~1.0.0",
     "isstream": "~0.1.2",