chore(package): upgrade commitlint config to version 6

Author: SimenB

package.json

@@ -22,7 +22,7 @@
   },
   "devDependencies": {
     "@commitlint/cli": "^6.0.1",
-    "@commitlint/config-conventional": "^5.1.3",
+    "@commitlint/config-conventional": "^6.0.2",
     "eslint": "^4.10.0",
     "eslint-config-prettier": "^2.7.0",
     "eslint-plugin-prettier": "^2.3.1",