build: update build process

Author: Scrum

package.json

@@ -16,7 +16,7 @@
     "node": ">=6"
   },
   "scripts": {
-    "version": "conventional-changelog -i changelog.md -s -r 0 && git commit -am \"build: update changelog\"",
+    "version": "conventional-changelog -i changelog.md -s -r 0 && git add changelog.md && git commit -m \"build: update changelog\"",
     "prepare": "npm run build",
     "build": "rimraf lib && babel src -d lib",
     "test": "nyc ava",