chore(package): update cz-conventional-changelog to version 3.1.0

Closes #15

Author: greenkeeper[bot]

package.json

@@ -26,7 +26,7 @@
   },
   "devDependencies": {
     "commitizen": "^2.9.5",
-    "cz-conventional-changelog": "^1.2.0",
+    "cz-conventional-changelog": "^3.1.0",
     "semantic-release": "^7.0.1",
     "standard": "^10.0.1"
   },