chore(package): update unity-api to version 3.1.0

Closes #27

Author: greenkeeper[bot]

package.json

@@ -74,7 +74,7 @@
     "nyc": "^10.0.0",
     "rimraf": "^2.5.4",
     "sinon": "^2.0.0",
-    "unity-api": "^1.0.3",
+    "unity-api": "^3.1.0",
     "validate-commit-msg": "^2.10.1"
   },
   "ava": {