Bump koa from 2.15.4 to 2.16.1 in /example/koa (#85)

Bumps [koa](https://github.com/koajs/koa) from 2.15.4 to 2.16.1.
- [Release notes](https://github.com/koajs/koa/releases)
- [Changelog](https://github.com/koajs/koa/blob/master/History.md)
- [Commits](koajs/koa@2.15.4...v2.16.1)

---
updated-dependencies:
- dependency-name: koa
  dependency-version: 2.16.1
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

example/koa/package.json

@@ -12,7 +12,7 @@
     "i18next": "23.5.1",
     "i18next-fs-backend": "2.2.0",
     "i18next-http-middleware": "3.4.0",
-    "koa": "2.15.4",
+    "koa": "2.16.1",
     "koa-body": "6.0.1",
     "koa-mount": "4.0.0",
     "koa-static": "5.0.0"