fix(package): update express to version 4.17.1

Closes #91

Author: greenkeeper[bot]

package.json

@@ -28,7 +28,7 @@
     "camelcase-keys": "~5.1.0",
     "connect-redis": "~3.4.1",
     "dotenv-safe": "~6.1.0",
-    "express": "~4.16.4",
+    "express": "~4.17.1",
     "http-status": "~1.3.2",
     "joi": "~14.3.1",
     "jsonade": "~1.4.1",