chore(package): update semantic-release to version 15.1.6

Closes #21

Author: greenkeeper[bot]

package.json

@@ -61,7 +61,7 @@
     "inquirer": "^4.0.1",
     "jest": "^22.0.4",
     "prettier": "^1.9.2",
-    "semantic-release": "^11.0.2"
+    "semantic-release": "^15.1.6"
   },
   "jest": {
     "coverageReporters": [