fix(deps): update dependency koa to v2.16.2 [security]

Author: renovate[bot]

code/koa/package.json

@@ -3,6 +3,6 @@
   "version": "0.0.1",
   "main": "index.js",
   "dependencies": {
-    "koa": "2.15.4"
+    "koa": "2.16.2"
   }
 }