Bump koa from 2.15.3 to 2.16.1

Bumps [koa](https://github.com/koajs/koa) from 2.15.3 to 2.16.1.
- [Release notes](https://github.com/koajs/koa/releases)
- [Changelog](https://github.com/koajs/koa/blob/master/History.md)
- [Commits](https://github.com/koajs/koa/compare/2.15.3...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>

package.json

@@ -13,7 +13,7 @@
     "@koa/multer": "^3.0.2",
     "@koa/router": "^13.1.0",
     "file-type": "^16.5.4",
-    "koa": "^2.15.3",
+    "koa": "^2.16.1",
     "koa-logger": "^3.2.1",
     "koa-sendfile": "^3.0.0",
     "koa-static": "^5.0.0",