chore(package): update conventional-changelog-cli to version 2.0.21

Closes #9

Author: greenkeeper[bot]

package.json

@@ -25,7 +25,7 @@
     "chai": "4.2.0",
     "chai-as-promised": "7.1.1",
     "commitizen": "3.0.5",
-    "conventional-changelog-cli": "2.0.11",
+    "conventional-changelog-cli": "2.0.21",
     "cz-conventional-changelog": "2.1.0",
     "husky": "1.3.1",
     "jsonlint": "1.6.3",