chore(package): update commitizen to version 3.1.0

Closes #2

Author: greenkeeper[bot]

package.json

@@ -43,7 +43,7 @@
   "dependencies": {},
   "devDependencies": {
     "codecov": "^3.1.0",
-    "commitizen": "3.0.5",
+    "commitizen": "3.1.0",
     "cz-conventional-changelog": "2.1.0",
     "ghooks": "2.0.4",
     "jest": "^23.6.0",