chore(package): update @commitlint/config-conventional to version 7.6.0

Closes #23

Author: greenkeeper[bot]

package.json

@@ -44,7 +44,7 @@
   },
   "devDependencies": {
     "@commitlint/cli": "6.1.3",
-    "@commitlint/config-conventional": "6.1.3",
+    "@commitlint/config-conventional": "7.6.0",
     "@storybook/react": "3.4.0",
     "babel-cli": "6.26.0",
     "babel-preset-es2015": "6.24.1",