chore(package): update semantic-release to version 15.4.1

Closes #168

Author: greenkeeper[bot]

package.json

@@ -28,7 +28,7 @@
     "pouchdb-replication": "^6.0.7",
     "proxyquire": "^1.7.6",
     "rimraf": "^2.4.3",
-    "semantic-release": "^12.2.2",
+    "semantic-release": "^15.4.1",
     "simple-mock": "^0.8.0",
     "standard": "^11.0.0",
     "tap-spec": "^4.1.0",