chore(deps): update dependency koa to v2.15.4 [security]

Author: renovate-bot

package-lock.json

@@ -57,7 +57,7 @@
     "@types/mocha": "7.0.2",
     "@types/node": "18.18.14",
     "@types/sinon": "10.0.20",
-    "koa": "2.13.1",
+    "koa": "2.15.4",
     "nyc": "15.1.0",
     "rimraf": "5.0.10",
     "semver": "7.6.3",