chore(package): update zombie to version 6.1.1

Closes #454

Author: greenkeeper[bot]

package.json

@@ -70,6 +70,6 @@
     "steal-tools": "^1.8.2",
     "test-saucelabs": "0.0.3",
     "testee": "^0.7.0",
-    "zombie": "^5.0.5"
+    "zombie": "^6.1.1"
   }
 }