Bump debug from 2.6.9 to 4.1.1

Bumps [debug](https://github.com/visionmedia/debug) from 2.6.9 to 4.1.1.
- [Release notes](https://github.com/visionmedia/debug/releases)
- [Commits](debug-js/debug@2.6.9...4.1.1)

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

Author: dependabot-support

package-lock.json

@@ -19,7 +19,7 @@
         "cookie-session": "^2.0.0-beta.3",
         "cors": "^2.8.5",
         "cryptiles": "^4.1.3",
-        "debug": "~2.6.9",
+        "debug": "~4.1.1",
         "dotenv": "^6.2.0",
         "express": "~4.16.0",
         "express-validator": "^5.3.1",