chore(package): update commitizen to version 4.0.1

Closes #295

Author: greenkeeper[bot]

package.json

@@ -55,7 +55,7 @@
     "@commitlint/config-conventional": "^6.0.2",
     "@commitlint/prompt": "^6.0.2",
     "chai": "^4.1.2",
-    "commitizen": "^2.9.6",
+    "commitizen": "^4.0.1",
     "coveralls": "^3.0.0",
     "husky": "^0.14.3",
     "istanbul": "^0.4.5",