chore(package): update cz-conventional-changelog to version 3.1.1

Closes #49

Author: greenkeeper[bot]

package.json

@@ -38,7 +38,7 @@
     "babel-preset-stage-2": "^6.22.0",
     "codecov.io": "^0.1.6",
     "commitizen": "^2.9.5",
-    "cz-conventional-changelog": "^2.0.0",
+    "cz-conventional-changelog": "^3.1.1",
     "eslint": "^3.19.0",
     "eslint-config-airbnb": "^15.0.1",
     "eslint-plugin-import": "^2.6.1",