chore(package): update semantic-release to version 12.4.0

Closes #302

Author: greenkeeper[bot]

package.json

@@ -32,7 +32,7 @@
     "istanbul": "^0.4.5",
     "mocha": "^3.2.0",
     "pre-git": "^3.15.3",
-    "semantic-release": "^8.0.3"
+    "semantic-release": "^12.4.0"
   },
   "config": {
     "pre-git": {