fix(package): update semver to version 6.1.0

Closes #55

Author: greenkeeper[bot]

package.json

@@ -19,7 +19,7 @@
     "passport": "^0.4.0",
     "passport-hawk": "^4.0.0",
     "scrypt": "^6.0.3",
-    "semver": "^5.4.1"
+    "semver": "^6.1.0"
   },
   "devDependencies": {
     "babel-eslint": "^8.2.2",