chore(package): update commitizen to version 4.0.5

Closes #125

Author: greenkeeper[bot]

package.json

@@ -67,7 +67,7 @@
     "bootstrap": "3.3.7",
     "codecov": "^2.0.2",
     "codelyzer": "3.0.1",
-    "commitizen": "2.9.6",
+    "commitizen": "4.0.5",
     "core-js": "^2.4.1",
     "cz-conventional-changelog": "2.0.0",
     "jasmine-core": "2.6.2",