chore(package): update @commitlint/config-conventional to version 8.3.4

Closes #20

Author: greenkeeper[bot]

package.json

@@ -72,7 +72,7 @@
   },
   "devDependencies": {
     "@commitlint/cli": "^8.3.4",
-    "@commitlint/config-conventional": "^7.1.2",
+    "@commitlint/config-conventional": "^8.3.4",
     "@types/jest": "^23.3.2",
     "@types/node": "^10.11.0",
     "colors": "^1.3.2",