chore(package): update sinon to version 5.0.0 (#656)

Author: greenkeeper[bot]

package.json

@@ -81,7 +81,7 @@
     "passport-strategy": "^1.0.0",
     "primus": "^7.0.0",
     "semistandard": "^12.0.0",
-    "sinon": "^4.0.0",
+    "sinon": "^5.0.0",
     "sinon-chai": "^3.0.0",
     "socket.io-client": "^2.0.0",
     "superagent": "^3.0.0",