chore(package): update semantic-release to version 15.13.18

Author: greenkeeper[bot]

package.json

@@ -58,7 +58,7 @@
     "parse-json": "^4.0.0",
     "rollup": "^0.60.0",
     "rollup-plugin-babel": "^3.0.3",
-    "semantic-release": "^15.13.13",
+    "semantic-release": "^15.13.18",
     "sinon": "^6.0.0",
     "sinon-stub-promise": "^4.0.0",
     "travis-deploy-once": "^5.0.0",