Bump koa from 2.15.0 to 2.15.2

Bumps [koa](https://github.com/koajs/koa) from 2.15.0 to 2.15.2.
- [Changelog](https://github.com/koajs/koa/blob/2.15.2/History.md)
- [Commits](koajs/koa@2.15.0...2.15.2)

---
updated-dependencies:
- dependency-name: koa
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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

package.json

@@ -15,7 +15,7 @@
   },
   "dependencies": {
     "finished": "^1.2.2",
-    "koa": "^2.15.0",
+    "koa": "^2.15.2",
     "koa-body": "^6.0.1",
     "koa-router": "^12.0.1"
   },