Upgrade winston

Our log library got a new major version which should be implemented.

That's exactly what this patch does. Implementing the new version of the
logging library.

Signed-off-by: Sheogorath <sheogorath@shivering-isles.com>

package.json

@@ -129,7 +129,7 @@
     "velocity-animate": "^1.4.0",
     "visibilityjs": "^1.2.4",
     "viz.js": "^1.7.0",
-    "winston": "^2.3.0",
+    "winston": "^3.1.0",
     "ws": "^6.0.0",
     "xss": "^1.0.3"
   },