Bump express from 4.16.3 to 4.16.4

Bumps [express](https://github.com/expressjs/express) from 4.16.3 to 4.16.4.
- [Release notes](https://github.com/expressjs/express/releases)
- [Changelog](https://github.com/expressjs/express/blob/master/History.md)
- [Commits](expressjs/express@4.16.3...4.16.4)

Signed-off-by: dependabot[bot] <support@dependabot.com>

Author: dependabot-support

package-lock.json

@@ -21,7 +21,7 @@
     "cryptiles": "^4.1.3",
     "debug": "~2.6.9",
     "dotenv": "^5.0.1",
-    "express": "~4.16.0",
+    "express": "~4.16.4",
     "express-validator": "^5.2.0",
     "express-winston": "^2.5.1",
     "handlebars": "^4.0.12",