chore(package): update commitizen to version 4.0.1

Closes #11

Author: greenkeeper[bot]

package.json

@@ -56,7 +56,7 @@
     "babel-core": "^6.26.3",
     "babel-jest": "^23.6.0",
     "codecov": "^3.1.0",
-    "commitizen": "^3.0.5",
+    "commitizen": "^4.0.1",
     "coveralls": "^3.0.2",
     "cz-conventional-changelog": "^2.1.0",
     "eslint": "^5.9.0",