chore(package): update all-contributors-cli to version 6.8.0

Closes #10

Author: greenkeeper[bot]

package.json

@@ -37,7 +37,7 @@
   "devDependencies": {
     "@commitlint/cli": "^6.1.3",
     "@commitlint/config-conventional": "^6.1.3",
-    "all-contributors-cli": "^4.6.0",
+    "all-contributors-cli": "^6.8.0",
     "babel-eslint": "^8.2.3",
     "babel-jest": "23.0.1",
     "commitizen": "^2.9.6",