chore(package): update dredd to version 12.1.0

Closes #104

Author: greenkeeper[bot]

package.json

@@ -21,7 +21,7 @@
   },
   "devDependencies": {
     "chai": "^4.1.2",
-    "dredd": "^5.1.11",
+    "dredd": "^12.1.0",
     "eslint": "^5.3.0",
     "fibers": "^3.0.0",
     "mocha": "^5.2.0",