chore(package): update conventional-changelog-core to version 3.1.3

Closes #14

Author: greenkeeper[bot]

package.json

@@ -34,7 +34,7 @@
     "better-than-before": "^1.0.0",
     "chai": "^4.0.0",
     "commitizen": "2.9.6",
-    "conventional-changelog-core": "^1.5.0",
+    "conventional-changelog-core": "^3.1.3",
     "coveralls": "^3.0.0",
     "ghooks": "1.3.2",
     "git-dummy-commit": "^1.3.0",