chore(package): update semver to version 5.2.0 (#271)

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -62,7 +62,7 @@
     "proxyquire": "1.7.9",
     "rimraf": "2.5.2",
     "semantic-release": "4.3.5",
-    "semver": "5.1.1",
+    "semver": "5.2.0",
     "sinon": "1.17.3"
   },
   "dependencies": {