fix(package): update express-handlebars to version 4.0.3

Closes #141

Author: greenkeeper[bot]

package.json

@@ -40,7 +40,7 @@
     "debug": "^4.0.0",
     "dotenv": "^6.0.0",
     "express": "^4.16.2",
-    "express-handlebars": "^3.0.0",
+    "express-handlebars": "^4.0.3",
     "imgur": "^0.3.1",
     "lowdb": "^1.0.0",
     "morgan": "^1.9.0",