chore(package): update commitizen to version 4.0.4

Closes #305

Author: greenkeeper[bot]

Diff for: package.json

@@ -88,7 +88,7 @@
     "@types/jest": "^23.3.2",
     "@types/node": "^10.11.0",
     "colors": "^1.3.2",
-    "commitizen": "^3.0.0",
+    "commitizen": "^4.0.4",
     "coveralls": "^3.0.2",
     "cross-env": "^5.2.0",
     "cz-conventional-changelog": "^2.1.0",