Update dependency should to v13

Author: renovate-bot

package.json

@@ -27,7 +27,7 @@
   "devDependencies": {
     "jshint": "2.11.0",
     "mocha": "3.5.3",
-    "should": "11.2.1",
+    "should": "13.2.3",
     "sinon": "2.4.1"
   },
   "license": "MIT",