chore(package): update pre-git to version 3.9.0 (#10)

Author: greenkeeperio-bot

package.json

@@ -13,7 +13,7 @@
   "devDependencies": {
     "eslint": "^2.4.0",
     "mocha": "^2.4.5",
-    "pre-git": "3.8.4",
+    "pre-git": "3.9.0",
     "semantic-release": "^4.3.5"
   },
   "config": {