Bump koa from 2.13.4 to 2.15.4

Bumps [koa](https://github.com/koajs/koa) from 2.13.4 to 2.15.4.
- [Release notes](https://github.com/koajs/koa/releases)
- [Changelog](https://github.com/koajs/koa/blob/2.15.4/History.md)
- [Commits](koajs/koa@2.13.4...2.15.4)

---
updated-dependencies:
- dependency-name: koa
  dependency-type: direct:production
...

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

Author: dependabot[bot]

package-lock.json

@@ -42,7 +42,7 @@
     "inflection": "^1.13.4",
     "jsonwebtoken": "^9.0.0",
     "knex": "^2.3.0",
-    "koa": "2.13.4",
+    "koa": "2.15.4",
     "koa-body": "^5.0.0",
     "koa-compose": "^4.1.0",
     "ws": "^8.8.1"