chore(package): update cz-conventional-changelog to version 3.1.0

Closes #90

Author: greenkeeper[bot]

package.json

@@ -35,7 +35,7 @@
   },
   "devDependencies": {
     "coveralls": "^2.11.12",
-    "cz-conventional-changelog": "^2.0.0",
+    "cz-conventional-changelog": "^3.1.0",
     "jasmine-core": "^2.6.2",
     "karma": "^2.0.0",
     "karma-chrome-launcher": "^2.2.0",