fix(package): update jsonwebtoken to version 8.1.1

Closes #15

Author: greenkeeper[bot]

package.json

@@ -12,7 +12,7 @@
     "ejs": "~2.5.2",
     "express": "~5.0.0-alpha.3",
     "express-jwt": "^5.1.0",
-    "jsonwebtoken": "^7.1.9",
+    "jsonwebtoken": "^8.1.1",
     "mongoose": "^4.6.7",
     "morgan": "~1.8.0",
     "passport": "^0.3.0",